Breakthrough SARS-CoV-2 infection and disease flares in patients with rheumatoid arthritis: result from COVAD e-survey study

COVID-19 has been suggested as a possible trigger of disease flares in patients with rheumatoid arthritis (RA). However, factors associated with disease flares remain unknown. This study aimed to identify factors associated with breakthrough infection (BIs) and disease flares in patients with RA following COVID-19. We analysed data from RA patients who participated in the COVID-19 vaccination in autoimmune diseases (COVAD) study. Demographic data, patient-reported outcomes, comorbidities, pharmacologic treatment and details regarding disease flares were extracted from the COVAD database. Factors associated with disease flare-ups were determined by multivariate logistic regression analysis. The analysis comprised 1928 patients with RA who participated in the COVAD study. Younger age, Caucasian ethnicity, comorbidities with obstructive chronic pulmonary disease and asthma were associated with COVID-19 breakthrough infection. Moreover, younger age (odds ratio (OR): 0.98, 95% CI 0.96-0.99, p < 0.001), ethnicity other than Asian, past history of tuberculosis (OR: 3.80, 95% CI 1.12-12.94, p = 0.033), treatment with methotrexate (OR: 2.55, 95% CI: 1.56-4.17, p < 0.001), poor global physical health (OR: 1.07, 95% CI 1.00-1.15, p = 0.044) and mental health (OR: 0.91, 95% CI 0.87-0.95, p < 0.001) were independent factors associated disease flares in patients with RA. Our study highlights the impact of socio-demographic factors, clinical characteristics and mental health on disease flares in patients with RA. These insights may help determine relevant strategies to proactively manage RA patients at risk of flares.

Assessment of the neutralizing antibody response in Omicron breakthrough cases in healthcare workers who received the homologous booster of Moderna mRNA-1273

Vaccines against SARS-CoV-2 were developed during the pandemic including the BNT162b2 and the mRNA-1273. We evaluated the levels of binding antibodies against the receptor binding domain and the levels of NAbs in individuals who developed a breakthrough infection after having received three doses of mRNA-1273. A total of 51 participants were included. The breakthrough group was compared to a 1:1 matched-control group. Among the 51 individuals, 18 (35%) developed a breakthrough infection. The GMT of NAbs against the BA.1 in the BK population was 278.1 (95%CI: 168.1-324.1). This titer was significantly lower compared to the matched-control group when considering all data (GMT = 477.4; 95%CI: 316.2-541.0; p = 0.0057). Results were similar for the BA.5 (GMT = 152.0 (95%CI: 76.9-172.9) for breakthrough and 262.0 (95%CI: 171.3-301.8) for control (p = 0.0043)). Our study found that individuals receiving the mRNA-1273 booster and who developed a breakthrough infection presented lower levels of binding antibodies and NAbs before the infection as compared to a matched-control group.

Effectiveness of enterovirus A71 vaccine against pediatric HFMD and disease profile of post-vaccination infection

BACKGROUND

Vaccination has been proven effective against infection with enterovirus A71 (EV-A71) in clinical trials, but vaccine effectiveness in real-world situations remains incompletely understood. Furthermore, it is not clear whether previous vaccination will result in symptom attenuation among post-vaccinated cases.

METHODS

Based on long-term data extracted from the only designed referral hospital for infectious diseases, we used a test-negative case-control design and multivariate logistic regression models to analyze the effectiveness of EV-A71 vaccine against hand, foot and mouth disease (HFMD). And then, generalized linear regression models were used to evaluate the associations between prior vaccination and disease profiles.

RESULTS

We selected 4883 inpatients for vaccine efficacy estimations and 2188 inpatients for disease profile comparisons. Vaccine effectiveness against EV-A71-induced HFMD for complete vaccination was 63.4 % and 51.7 % for partial vaccination. The vaccine effectiveness was higher among cases received the first dose within 12 months. No protection was observed against coxsackievirus (CV) A6-, CV-A10- or CV-A16-associated HFMD among children regardless of vaccination status. Completely vaccinated cases had shorter hospital stay and disease course compared to unvaccinated cases (P < 0.05).

CONCLUSIONS

These findings reiterate the need to continue the development of a multivalent vaccine or combined vaccines, and have implications for introducing optimized vaccination strategies.

Clinical characteristics and outcomes of vaccinated patients hospitalised with SARS-CoV-2 breakthrough infection: Multi-IPV, a multicentre study in Northern Italy

BACKGROUND

Despite the well-known efficacy of anti-COVID-19 vaccines in preventing morbidity and mortality, several vaccinated individuals are diagnosed with SARS-CoV-2 breakthrough infection, which might require hospitalisation. This multicentre, observational, and retrospective study aimed to investigate the clinical characteristics and outcomes of vaccinated vs. non-vaccinated patients, both hospitalised with SARS-CoV-2 infection in 3 major hospitals in Northern Italy.

METHODS

Data collection was retrospective, and paper and electronic medical records of adult patients with a diagnosed SARS-CoV-2 infection were pseudo-anonymised and analysed. Vaccinated and non-vaccinated individuals were manually paired, using a predetermined matching criterion (similar age, gender, and date of hospitalisation). Demographic, clinical, treatment, and outcome data were compared between groups differing by vaccination status using Pearson's Chi-square and Mann-Whitney tests. Moreover, multiple logistic regression analyses were performed to assess the impact of vaccination status on ICU admission or intra-hospital mortality.

RESULTS

Data from 360 patients were collected. Vaccinated patients presented with a higher prevalence of relevant comorbidities, like kidney replacement therapy or haematological malignancy, despite a milder clinical presentation at the first evaluation. Non-vaccinated patients required intensive care more often than their vaccinated counterparts (8.8% vs. 1.7%, p = 0.002). Contrariwise, no difference in intra-hospital mortality was observed between the two groups (19% vs. 20%, p = 0.853). These results were confirmed by multivariable logistic regressions, which showed that vaccination was significantly associated with decreased risk of ICU admission (aOR=0.172, 95%CI: 0.039-0.542, p = 0.007), but not of intra-hospital mortality (aOR=0.996, 95%CI: 0.582-1.703, p = 0.987).

CONCLUSIONS

This study provides real-world data on vaccinated patients hospitalised with COVID-19 in Northern Italy. Our results suggest that COVID-19 vaccination has a protective role in individuals with higher risk profiles, especially regarding the need for ICU admission. These findings contribute to our understanding of SARS-CoV-2 infection outcomes among vaccinated individuals and emphasise the importance of vaccination in preventing severe disease, particularly in those countries with lower first-booster uptake rates.

Infection-mediated immune response in SARS-CoV-2 breakthrough infection and implications for next-generation COVID-19 vaccine development

Post-vaccination infections, termed breakthrough infections, occur after the virus infection overcomes the vaccine-induced immune barrier. During the early stages of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron wave, high serum-neutralizing antibody titers against the Omicron variant were detected in individuals with breakthrough infections as well as those who received a third vaccine dose (i.e., booster recipients). Additionally, these cases indicated that Omicron antigens triggered an immune response that differed from that triggered by the vaccine strain before analysis of the effectiveness of new vaccines updated for the Omicron variants. Moreover, the magnitude and breadth of neutralizing antibody titers induced by breakthrough infections are correlated with the upper respiratory viral load at diagnosis and the duration between vaccination and infection, respectively. Unlike booster vaccine recipients, patients with breakthrough infections have varying durations between vaccination and infection. Accordingly, optimal booster vaccination intervals may be estimated based on the cross-neutralizing antibody response induced over time. Examination of breakthrough infection cases has provided valuable insights that could not be yielded by only examining vaccinated individuals alone. These insights include estimates of vaccine-induced immunity against SARS-CoV-2 variants and the various factors related to the clinical status. This review describes the immune response elicited by breakthrough infections; specifically, it discusses factors that affect the magnitude and breadth of serum antibody titers as well as the appropriate booster vaccination strategy. This review provides key aspects that could contribute to developing next-generation COVID-19 vaccines through breakthrough infection cases.

Estimation of the effect of vaccination in critically ill COVID-19 patients, analysis using propensity score matching

BACKGROUND

Vaccination helped in reducing mortality and disease severity due to COVID-19. Some patients can develop breakthrough infections. The effect of vaccination in critically ill patients admitted with breakthrough infections is not well studied. We designed a study to estimate the effect of vaccination on ICU mortality in critically ill COVID-19 patients by using propensity score matching.

METHODS

We included patients from 15th June 2020 to 31st December 2021. Inclusion criteria were unvaccinated and vaccinated COVID-19 patients requiring intensive care unit (ICU) admission. The institutional ethics committee approval was obtained (institutional ethics committee, IEC 08/2023, Clinical trial registry, India CTRI/2023/01/049142). The primary outcome was ICU mortality. The secondary outcomes were the length of ICU stay and duration of mechanical ventilation. We used multivariable logistic regression (MLR) and propensity score matching (PSM) for the statistical analysis.

RESULTS

Total of 667 patients (79.31%) were unvaccinated and 174 (20.68%) vaccinated. The mean age was 57.11 [standard deviation (SD) 15.13], and 70.27% were males. The ICU mortality was 56.60% [95% confidence interval (CI) 53.24-60%]. The results of MLR and PSM method showed that vaccinated patients were less likely to be associated with mortality [adjusted odds ratio (AOR), 95% CI using logistic regression: 0.52 (0.29, 0.94), and by propensity score matching: 0.83 (0.77, 0.91)].

CONCLUSION

The findings of this study support COVID-19 vaccination as an effective method for reducing case fatality not only in the general population but also in critically ill patients, and it has important public health implications.

The appearance of anti-spike receptor binding domain immunoglobulin G4 responses after repetitive immunization with messenger RNA-based COVID-19 vaccines

OBJECTIVES

It is crucial to analyze the consequences of repeated messenger RNA (mRNA)-based COVID-19 vaccinations on SARS-CoV-2 spike receptor binding domain (RBD)-specific immunoglobulin (Ig)G subclass and the possible causal relationship with breakthrough infection.

METHODS

We examined the longitudinal kinetics of RBD-specific IgG subclass antibodies in sera after receiving the second, third, and fourth doses of mRNA-based COVID-19 vaccines in Japanese healthcare workers. Anti-RBD IgG subclass in sera of patients with COVID-19-infected who had not received the COVID-19 vaccine were also examined. We compared anti-RBD IgG subclass antibody titers in the serum of pre-breakthrough-infected vaccinees and non-infected vaccinees.

RESULTS

The seropositivity of anti-RBD IgG4 after the vaccination was 6.76% at 1 month after the second dose, gradually increased to 50.5% at 6 months after the second dose, and reached 97.2% at 1 month after the third dose. The seropositivity and titers of anti-RBD IgG1/IgG3 quickly reached the maximum at 1 month after the second dose and declined afterward. The elevated anti-RBD IgG4 Ab levels observed after repeated vaccinations were unlikely to increase the risk of breakthrough infection.

CONCLUSIONS

Repeated vaccinations induce delayed but drastic increases in anti-RBD IgG4 responses. Further functional investigations are needed to reveal the magnitude of the high contribution of spike-specific IgG4 subclasses after repeated mRNA-based COVID-19 vaccinations.

Clinical and immunological benefits of full primary COVID-19 vaccination in individuals with SARS-CoV-2 breakthrough infections: A prospective cohort study in non-hospitalized adults

BACKGROUND

SARS-CoV-2 variants of concern (VOC) may result in breakthrough infections (BTIs) in vaccinated individuals. The aim of this study was to investigate the effects of full primary (two-dose) COVID-19 vaccination with wild-type-based SARS-CoV-2 vaccines on symptoms and immunogenicity of SARS-CoV-2 VOC BTIs.

METHODS

In a longitudinal multicenter controlled cohort study in Bavaria, Germany, COVID-19 vaccinated and unvaccinated non-hospitalized individuals were prospectively enrolled within 14 days of a PCR-confirmed SARS-CoV-2 infection. Individuals were visited weekly up to 4 times, performing a structured record of medical data and viral load assessment. SARS-CoV-2-specific antibody response was characterized by anti-spike-(S)- and anti-nucleocapsid-(N)-antibody concentrations, anti-S-IgG avidity and neutralization capacity.

RESULTS

A total of 300 individuals (212 BTIs, 88 non-BTIs) were included with VOC Alpha or Delta SARS-CoV-2 infections. Full primary COVID-19 vaccination provided a significant effectiveness against five symptoms (relative risk reduction): fever (33 %), cough (21 %), dysgeusia (22 %), dizziness (52 %) and nausea/vomiting (48 %). Full primary vaccinated individuals showed significantly higher 50 % inhibitory concentration (IC50) values against the infecting VOC compared to unvaccinated individuals at week 1 (269 vs. 56, respectively), and weeks 5-7 (1,917 vs. 932, respectively) with significantly higher relative anti-S-IgG avidity (78% vs. 27 % at week 4, respectively).

CONCLUSIONS

Full primary COVID-19 vaccination reduced symptom frequencies in non-hospitalized individuals with BTIs and elicited a more rapid and longer lasting neutralization capacity against the infecting VOC compared to unvaccinated individuals. These results support the recommendation to offer at least full primary vaccination to all adults to reduce disease severity caused by immune escape-variants.

Insufficient anti-spike RBD IgA responses after triple vaccination with intramuscular mRNA BNT162b2 vaccine against SARS-CoV-2

Objectives

This study aims to examine whether the parenterally administered mRNA-based COVID-19 vaccines can induce sufficient mucosal-type IgA responses to prevent SARS-CoV-2 transmission.

Methods

We examined the longitudinal kinetics of SARS-CoV-2 spike RBD-specific IgA and IgG responses in sera of Japanese healthcare workers (HCWs) after receiving two doses and the third dose of BNT162b2 mRNA vaccines. During the prospective cohort study, Omicron breakthrough infections occurred in 62 participants among 370 HCWs who had received triple doses of the vaccine. Pre-breakthrough sera of infected HCWs and non-infected HCWs were examined for the levels of anti-RBD IgA and IgG titers.

Results

The seropositivity of anti-RBD IgA at 1 M after the second vaccine (2D-1M) and after the third dose (3D-1M) was 65.4% and 87.4%, respectively, and wanes quickly. The boosting effect on anti-RBD Ab titers following breakthrough infections was more notable for anti-RBD IgA than for IgG. There were partial cause-relationships between the lower anti-RBD IgA or IgG at pre-breakthrough sera and the breakthrough infection.

Conclusions

Parenterally administered COVID-19 vaccines do not generate sufficient mucosal-type IgA responses despite strong systemic IgG responses to SARS-CoV-2. These results demonstrate the necessity and importance of reevaluating vaccine design and scheduling to efficiently increase oral or respiratory mucosal immunity against SARS-CoV-2.

The spike-specific TCRβ repertoire shows distinct features in unvaccinated or vaccinated patients with SARS-CoV-2 infection

BACKGROUND

The evolving variants of SARS-CoV-2 may escape immunity from prior infections or vaccinations. It's vital to understand how immunity adapts to these changes. Both infection and mRNA vaccination induce T cells that target the Spike protein. These T cells can recognize multiple variants, such as Delta and Omicron, even if neutralizing antibodies are weakened. However, the degree of recognition can vary among people, affecting vaccine efficacy. Previous studies demonstrated the capability of T-cell receptor (TCR) repertoire analysis to identify conserved and immunodominant peptides with cross-reactive potential among variant of concerns. However, there is a need to extend the analysis of the TCR repertoire to different clinical scenarios. The aim of this study was to examine the Spike-specific TCR repertoire profiles in natural infections and those with combined natural and vaccine immunity.

METHODS

A T-cell enrichment approach and bioinformatic tools were used to investigate the Spike-specific TCRβ repertoire in peripheral blood mononuclear cells of previously vaccinated (n = 8) or unvaccinated (n = 6) COVID-19 patients.

RESULTS

Diversity and clonality of the TCRβ repertoire showed no significant differences between vaccinated and unvaccinated groups. When comparing the TCRβ data to public databases, 692 unique TCRβ sequences linked to S epitopes were found in the vaccinated group and 670 in the unvaccinated group. TCRβ clonotypes related to spike regions S135-177, S264-276, S319-350, and S448-472 appear notably more prevalent in the vaccinated group. In contrast, the S673-699 epitope, believed to have super antigenic properties, is observed more frequently in the unvaccinated group. In-silico analyses suggest that mutations in epitopes, relative to the main SARS-CoV-2 variants of concern, don't hinder their cross-reactive recognition by associated TCRβ clonotypes.

CONCLUSIONS

Our findings reveal distinct TCRβ signatures in vaccinated and unvaccinated individuals with COVID-19. These differences might be associated with disease severity and could influence clinical outcomes.

TRIAL REGISTRATION

FESR/FSE 2014-2020 DDRC n. 585, Action 10.5.12, noCOVID19@UMG.

Response to: regarding the significance of anti-COVID-IgA antibody response in COVID-19 breakthrough infection

In response to Chen et al.'s comments on our paper regarding the significance of anti-COVID-IgA antibody response in COVID-19 breakthrough infection in vaccinated patients, we have highlighted the role and the scope of this paper in this correspondence. The role of anti-COVID-19-IgA is already known. The objective of the previous study was to see its role in breakthrough-infected patients. To analyse this effect, we recruited patients with COVID-19 infection after they were fully vaccinated and compared them with the vaccinated group who did not get the infection. Both groups were equally exposed to the virus as all of them were health care workers. We also showed that the anti-COVID-19-NP-IgA was absent in the healthy cohort of our study groups, signifying the absence of natural infection in them during this period. The article also highlights the importance of vaccinating all individuals including those who are immunosuppressed, as it prevents severe COVID-19 infection in these individuals. The physicians should be aware of the fact that immunosuppressed patients are more likely to get COVID-19 breakthrough infection. However, proper vaccination with booster doses prevents severe infection in them.

Identification of SARS-CoV-2 m6A modification sites correlate with viral pathogenicity

It has recently been found that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) m6A modifications can affect viral replication and function. However, no studies to date have shown a correlation between SARS-CoV-2 m6A modifications and viral pathogenicity. In this study, we analyzed m6A modification in 2,190,667 SARS-CoV-2 genomic RNAs. m6A modifications of SARS-CoV-2 from different lineages, causing mild or severe COVID-19 and showing breakthrough for different vaccines were analyzed to explore correlations with viral pathogenicity. The results suggested that the presence of more m6A modifications in the SARS-CoV-2 N region (positive strand) correlates with weaker pathogenicity. In addition, we identified three m6A modification sites correlating with weak pathogenicity (924 in ORF1ab, 15,659 in ORF1ab, 28,288 in N, 28,633 in N and 29,385 in N, 29,707 in 3'UTR) and one with strong pathogenicity (74 in 5'UTR). These results provide new information for understanding the prevalence of SARS-CoV-2 and controlling the virus.

Association Between Low Anti-spike Antibody Levels After the Third Dose of SARS-CoV-2 Vaccination and Hospitalization due to Symptomatic Breakthrough Infection in Kidney Transplant Recipients

Background

Whether anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibody levels post-third coronavirus disease (COVID-19) vaccination correlate with worse outcomes due to breakthrough infection is unclear. We evaluated the association between anti-SARS-CoV-2 antibody levels and symptomatic breakthrough infection or hospitalization during the Omicron surge in kidney transplant recipients.

Methods

In total, 287 kidney transplant recipients expected to receive a third vaccination were enrolled between November 2021 and February 2022. The Abbott SARS-CoV-2 IgG II Quant test (Abbott, Chicago, IL, USA) was performed within three weeks before and four weeks after the third vaccination. The incidence of symptomatic breakthrough infection and hospitalization from two weeks to four months post-third vaccination was recorded.

Results

After the third vaccination, the seropositive rate and median antibody titer of the 287 patients increased from 57.1% to 82.2% and from 71.7 (interquartile range [IQR] 7.2-402.8) to 1,612.1 (IQR 153.9-5,489.1) AU/mL, respectively. Sixty-four (22.3%) patients had symptomatic breakthrough infections, of whom 12 required hospitalization. Lower anti-receptor-binding domain (RBD) IgG levels (<400 AU/mL) post-third vaccination were a risk factor for symptomatic breakthrough infection (hazard ratio [HR]=3.46, P<0.001). Anti-RBD IgG levels <200 AU/mL were a critical risk factor for hospitalization (HR=36.4, P=0.007).

Conclusions

Low anti-spike IgG levels after third vaccination in kidney transplant recipients were associated with symptomatic breakthrough infection and, particularly, with hospitalization during the Omicron surge. These data can be used to identify patients requiring additional protective measures, such as passive immunization using monoclonal antibodies.

Significance of Anti-COVID-IgA antibody response in COVID-19 breakthrough infection in vaccinated patients - a single-centered study from Pakistan

An increasing number of breakthrough-COVID-19-vaccinated individuals are being reported across the world. Humoral immunity has a crucial role in combating infection. In this study, we aimed to assess the importance of anti-COVID-S1-IgA and anti-COVID-NP-IgA in confirmed COVID-19 after vaccination (breakthrough infection group). Blood samples were collected from the breakthrough infection group within one week of breakthrough infections (n = 34). A second sample was also collected after 4 to 8 weeks (n = 27). Blood samples of healthy individuals (n = 29) were collected 4-8 weeks after the completion of vaccination. Anti-COVID-S1-IgA and anti-COVID-NP-IgA were detected by ELISA. Statistical analysis was performed using IBM SPSS version 24. In this study, we found a higher positivity rate for anti-COVID-S1-IgA in the breakthrough infection group (70% vs. 28% in healthy individuals). Anti-COVID-NP-IgA was not found in the control group (11% in the breakthrough infection group vs. 0 in healthy individuals). In the breakthrough-infected group, the positivity rate of anti-COVID-NP-IgA decreased significantly (median titers 16.9 IU/ml decreased to 4.2 IU/ml) p = 0.001), while anti-COVID-S1-IgA increased over a period of 4-8 weeks (9.35-16.35 IU/ml). Importantly, IgA response to both COVID-19 NP and S1 antigens was not found in 13 patients at initial testing. The findings of this study show that serum IgA may have a role both in breakthrough infections and also in the prevention of severe infection. Sluggish anti-COVID-19-IgA antibody response may be responsible for the occurrence of COVID-19 infection in breakthrough infection. On the other hand, more sustained anti-COVID-19-S1-IgA over a longer period of time may have a role in preventing these patients from severe infections and hospitalization. However, a study on a larger sample size including patients with severe disease after vaccination is required to prove this hypothesis. To the best of our knowledge, this is the first study reporting the importance of serum IgA in breakthrough-infected patients from our region.

Long-term outcomes of COVID-19 vaccination in patients with rare and complex connective tissue diseases: The ERN-ReCONNET VACCINATE study

Background

Vaccination is one of the most important measures to contain the COVID-19 pandemic, especially for frail patients. VACCINATE is a multicentre prospective observational study promoted by the European Reference Network on Rare and Complex Connective Tissue and Musculoskeletal Diseases (ERN ReCONNET) aimed at assessing the long-term outcomes of COVID-19 vaccination in patients with rare and complex connective tissue diseases (rcCTDs) in terms of efficacy and safety.

Methods

Adult rcCTDs patients were eligible for recruitment. Demographic, clinical and vaccination data were collected at enrolment. Follow-up visits were scheduled 4, 12, 24, 36 and 48 weeks after completion of the first vaccination cycle; data on adverse events, disease exacerbations and the occurrence of new SARS-CoV-2 infections were collected at these time-points.

Findings

365 rcCTDs patients (87 % female, mean age 51.8 ± 14.6 years) were recruited. Overall, 200 patients (54.8 %) experienced at least one adverse event, generally mild and in most cases occurring early after the vaccination. During follow-up, 55 disease exacerbations were recorded in 39 patients (10.7 %), distributed over the entire observation period, although most frequently within 4 weeks after completion of the vaccination cycle. The incidence of new SARS-CoV-2 infections was 8.9 per 1000 person-months, with no cases within 12 weeks from vaccine administration and an increasing trend of infections moving away from the primary vaccination cycle. Only one case of severe COVID-19 was reported during the study period.

Interpretation

COVID-19 vaccination seems effective and safe in rcCTDs patients. The rate of new infections was rather low and serious infections were uncommon in our cohort. No increased risk of disease flares was observed compared to previous disease history; however, such exacerbations may be potentially severe, emphasising the need for close monitoring of our patients.

Assessment of vaccinations and breakthrough infections after adjustment of the dynamic zero-COVID-19 strategy in China: an online survey

Coronavirus disease 2019 (COVID-19) cases in China has grown rapidly after adjustment of the dynamic zero-COVID-19 strategy. However, how different vaccination states affect symptoms, severity and post COVID conditions was unclear. Here, we used an online questionnaire to investigate the infection status of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) among 11,897 participants, with 55.55% positive and 28.42% negative. The common COVID-19 symptoms were fatigue (73.31%), cough (70.02%), fever (65.25%) and overall soreness (58.64%); self-reported asymptomatic infection accounted for 0.7% of participants. The persistent symptoms at 1 month after infection included fatigue (48.7%), drowsiness (34.3%), cough (30.1%), decreased exercise ability (23.1%) and pharyngeal discomfort (19.4%), which was reduced by more than 200% at 2 months. Participants with complications such as chronic obstructive pulmonary disease, respiratory diseases, diabetes, hypertension, etc. have a higher proportion of hospitalization and longer recovery time (p < = 0.01). Multiple vaccination statuses reduced the infection (p < 0.001) and severity rates (p = 0.022) by varying degrees as well as reduced the risk of high fever (>39.1 °C), chills, diarrhea and ageusia/anosmia, respectively (p < 0.05). Vaccination may enhance some upper respiratory symptoms, including sore throat, nasal congestion and runny nose, respectively (p < 0.05). Participants who had been vaccinated within 3 months were better protected by helping reduce their risk of overall soreness, chills and ageusia/anosmia, respectively (p < 0.05). In conclusion, our work has updated the epidemic characteristics of the breakthrough infection (BTI) wave after the dynamic zero-COVID-19 strategy, providing data and insights on how different vaccination statuses affect COVID-19 symptoms and disease prognosis.

Distinct features of SARS-CoV-2 humoral immunity against Omicron breakthrough infection

BACKGROUND

SARS-CoV-2 Omicron breakthrough infection (Omicron-BTI) after vaccination has been frequently observed. A more detailed understanding of the humoral immunity against Omicron-BTI is required.

METHODS

We measured strain-specific live-virus based neutralizing activity, anti-spike IgG, and anti-receptor-binding domain (RBD) IgG titers in individuals with Omicron/BA.1-BTI and directly compared them with controls with diverse combinations of wild-type (WT) mRNA vaccination and infection history.

RESULTS

Omicron-BTI individuals showed markedly higher neutralizing titers against all the WT, Delta, and Omicron strains in convalescent sera, compared with unvaccinated Omicron-infection individuals with only Omicron neutralizing activity. Similar tendencies were found in strain-specific anti-spike and anti-RBD IgG titers. The Omicron-specificity (BA.1/WT neutralizing ratio), Omicron-neutralizing efficiency per antibody unit, and anti-Omicron RBD-directivity of anti-spike antibodies in Omicron-BTI individuals were all significantly lower than those in unvaccinated Omicron-infection individuals, but they were equivalent to or higher than those in uninfected vaccinees. The induction of Omicron-specific neutralizing activity after Omicron-BTI was not weakened for eight months from the last vaccination.

CONCLUSIONS

These findings suggest that cross-reactive vaccine-induced immunity was intensively stimulated following Omicron breakthrough infection, which contributed to Omicron neutralization. Measuring SARS-CoV-2 variant-specific antibody levels as well as neutralizing activity is useful for evaluating humoral immunity after breakthrough infection in the current situation of antigenic gaps between vaccinated and epidemic (Omicron sub-lineages) strains.

Optimizing antimicrobial prophylaxis strategies in acute leukemia patients: Assessing the efficacy of fluconazole

BACKGROUND

Acute myeloid (AML) and promyelocytic (APL) leukemia patients are at high risk for infection and mortality. While guidance for infection prevention is provided by the National Comprehensive Cancer Network (NCCN) and the American Society of Clinical Oncology (ASCO), each institution may vary in antimicrobial prophylaxis prescribing practices. The discrepancy may be explained by medication intolerance, cost, and low incidence of mold infections in leukemia patients. A recent meta-analysis demonstrated mortality benefits with the use of posaconazole, which was adopted by the NCCN. Despite known risks, it is unclear whether universal mold-active coverage is indicated for all AML and APL patients.

OBJECTIVE

To assess the incidence of breakthrough infections in AML and APL patients.

METHODS

This was a single-center, retrospective chart review of AML and APL patients receiving induction therapy at Baylor St Luke's Medical Center (BSLMC) between January 2019 and October 2021. The primary outcome assessed the incidence of breakthrough infections. Descriptive statistics were used to summarize the data.

RESULTS

A total of 55 patients were included and 54 (98%) had prolonged neutropenia with a median duration of 30 days. Five patients (9.3%) experienced breakthrough infections during induction while 21 individuals (38.9%) during the follow-up period. Aspergillus infections occurred in three patients receiving nonmold coverage compared to none on mold-active agents (p = 1.0) with no statistical difference in mortality.

CONCLUSION

Despite the majority of patients not receiving mold-active prophylaxis, nonmold-active prophylaxis may be sufficient with consideration of low aspergillosis incidence.

Clinical characteristics, outcomes, and risk factors of SARS-CoV-2 breakthrough infections among 572 fully vaccinated (BBIBP-CorV) hospitalized patients

Background

Breakthrough infections have been widely reported in vaccinated individuals. However, the clinical characteristics, outcomes, and risk factors of SARS-CoV-2 breakthrough infections among fully vaccinated (BBIBP-CorV) hospitalized patients have not yet been fully elucidated.

Methods

In the single-center cohort study conducted at Xiangya Hospital of Central South University, we enrolled the hospitalized COVID-19 patients who had received full (2 doses) vaccination with the BBIBP-CorV vaccine between December 5, 2022, and January 31, 2023. We collected and analyzed information related to clinical characteristics, laboratory results, treatments, outcomes and prognostic data. Univariate and multivariable Cox regression were performed to assess the impact of clinical characteristics and laboratory results on the composite outcome (including the initiation of endotracheal intubation, non-invasive respiratory support, intensive care unit admission, and all-cause death).

Results

A total of 572 COVID-19 hospitalized patients with fully vaccinated (BBIBP-CorV) were included. The median age of the patients was 66 years (IQR 53, 74). The most common symptoms included fever (347 [60.7 %]), dry cough (401 [70.1 %]), and expectoration (333 [58.2 %]). Among those with pre-existing chronic comorbidities, 44.2 % had hypertension and 20.5 % had diabetes. Laboratory tests revealed that the majority of patients (425/549 [77.4 %]) had normal white blood cell counts. Composite outcome occurred in 11.9 % of patients, with 96.7 % of patients discharged and 3.3 % of patients died. Multivariate Cox regression analyses suggested that the NLR >4 (adjusted HR, 5.50 [95%CI: 1.56-19.47]; P = 0.008), D-dimer >0.5 mg/ml (adjusted HR, 2.17 [95%CI: 1.03-4.59]; P = 0.042) and procalcitonin >0.1 ng/ml (adjusted HR, 3.22 [95%CI: 1.38-7.52]; P = 0.007) were independently associated with the composite outcome.

Conclusion

Breakthrough infection after being fully vaccinated (BBIBP-CorV) is more likely to occur in older patients and patients with pre-existing chronic comorbidities. NLR >4, D-dimer >0.5 mg/ml and procalcitonin >0.1 ng/ml were independent risk factors for composite outcome.

those following vaccine administration

PURPOSE

The term "breakthrough infection" of COVID-19 indicates that subjects who previously received COVID-19 vaccination became infected with COVID-19. This study compared the recurrence of audio-vestibular disorders following breakthrough infection of COVID-19 vs. those following vaccine administration.

PATIENTS AND METHODS

Fifty patients with previous known audio-vestibular disorders visited our clinic due to recurrence of inner ear symptoms following breakthrough infection of COVID-19 and were assigned to Group A. Another 50 patients who had recurrent inner ear symptoms following COVID-19 vaccination were assigned to Group B for comparison. The post-breakthrough infection interval is defined from date of breakthrough infection to the onset of inner ear symptoms, while the post-vaccination interval means the time from date of vaccination to the onset of inner ear symptoms. These two intervals were calculated and then compared.

RESULTS

The time from latest vaccination to the breakthrough infection of COVID-19 was 4 m (median), likely due to waning of IgG response. To the onset of inner ear symptoms, the post-breakthrough infection interval was 40d (median) for Group A, which was significantly longer than 10d (median) of the post-vaccination interval for Group B.

CONCLUSION

The post-breakthrough infection interval (median, 40d) is significantly longer than the post-vaccination interval (median, 10d) to exacerbate pre-existing audio-vestibular disorders. The reason is probably because an interval of 40d is related to IgG peak response following COVID-19 breakthrough infection, while that of 10d is responsible for IgG production after COVID-19 vaccination.

Correlation between specific antibody response to wild-type BNT162b2 booster and the risk of breakthrough infection with omicron variants: Impact of household exposure in hospital healthcare workers

BACKGROUND

The emergence of omicron variants exhibiting antigenic changes has led to an increase in breakthrough infection among individuals with a wild-type SARS-CoV-2 vaccine booster. The correlation between post-booster spike-specific antibodies and omicron infection risk remains unclear.

METHODS

This prospective cohort study included SARS-CoV-2-naive healthcare workers with three-dose BNT162b2. Post-booster spike-specific IgG and interferon-γ levels were measured. Breakthrough infection was documented during a 10-month omicron-predominant period. Household and healthcare contacts were followed to identify subsequent infections. The IgG titers were additionally measured at the end of follow-up, and the titers at exposure were estimated from the two-point titers.

RESULTS

Of 333 participants, 89 developed infection, of whom 37 (41.6 %) were household contacts. Kaplan-Meier curves indicated that higher IgG titers were significantly correlated with lower cumulative infection incidence (p = 0.029), whereas the interferon-γ levels were not (p = 0.926). Multivariate Cox analysis showed that increasing IgG titers were associated with a reduced hazard ratio (HR) of 0.26 (95% CI, 0.12-0.55). Household exposure posed a greater infection risk than healthcare exposure (HRs, 11.24 [6.88-18.40] vs. 2.82 [1.37-5.44]). The difference in geometric mean IgG titers of infected and uninfected participants was significant among household contacts (20,244 AU/mL vs. 13,842 AU/mL, p = 0.031). Estimation of IgG titers at exposure showed a significantly higher infection incidence in those exposed with titers of <3,000 AU/mL than in those with higher titers (79.2 % vs. 32.3 %, p < 0.001).

CONCLUSIONS

Spike-specific antibodies induced by a wild-type SARS-CoV-2 vaccine booster are suggested to be effective in protecting against omicron infection. Household exposure would be a significant source of infection for hospital healthcare workers.

Neutralising antibody responses against SARS-CoV-2 Omicron BA.4/5 and wild-type virus in patients with inflammatory bowel disease following three doses of COVID-19 vaccine (VIP): a prospective, multicentre, cohort study

Background

Patients with inflammatory bowel disease (IBD) receiving anti-TNF and JAK-inhibitor therapy have attenuated responses to COVID-19 vaccination. We aimed to determine how IBD treatments affect neutralising antibody responses against the Omicron BA.4/5 variant.

Methods

In this multicentre cohort study, we prospectively recruited 340 adults (69 healthy controls and 271 IBD) at nine UK hospitals between May 28, 2021 and March 29, 2022. The IBD study population was established (>12 weeks therapy) on either thiopurine (n = 63), infliximab (n = 45), thiopurine and infliximab combination therapy (n = 48), ustekinumab (n = 45), vedolizumab (n = 46) or tofacitinib (n = 24). Patients were excluded if they were being treated with any other immunosuppressive therapies. Participants had two doses of either ChAdOx1 nCoV-19 or BNT162b2 vaccines, followed by a third dose of either BNT162b2 or mRNA1273. Pseudo-neutralisation assays against SARS-CoV-2 wild-type and BA.4/5 were performed. The half maximal inhibitory concentration (NT50) of participant sera was calculated. The primary outcome was anti-SARS-CoV-2 neutralising response against wild-type virus and Omicron BA.4/5 variant after the second and third doses of anti-SARS-CoV-2 vaccine, stratified by immunosuppressive therapy, adjusting for prior infection, vaccine type, age, and interval between vaccination and blood collection. This study is registered with ISRCTN (No. 13495664).

Findings

Both heterologous (first two doses adenovirus vaccine, third dose mRNA vaccine) and homologous (three doses mRNA vaccine) vaccination strategies significantly increased neutralising titres against both wild-type SARS-CoV-2 virus and the Omicron BA.4/5 variant in healthy participants and patients with IBD. Antibody titres against BA.4/5 were significantly lower than antibodies against wild-type virus in both healthy participants and patients with IBD (p < 0.0001). Multivariable models demonstrated that neutralising antibodies against BA.4/5 after three doses of vaccine were significantly lower in patients with IBD on infliximab (Geometric Mean Ratio (GMR) 0.19 [0.10, 0.36], p < 0.0001), infliximab and thiopurine combination (GMR 0.25 [0.13, 0.49], p < 0.0001) or tofacitinib (GMR 0.43 [0.20, 0.91], p = 0.028), but not in patients on thiopurine monotherapy, ustekinumab, or vedolizumab. Breakthrough infection was associated with lower neutralising antibodies against wild-type (p = 0.037) and BA.4/5 (p = 0.045).

Interpretation

A third dose of a COVID-19 mRNA vaccine based on the wild-type spike glycoprotein significantly boosts neutralising antibody titres in patients with IBD. However, responses are lower against the Omicron variant BA.4/5, particularly in patients taking anti-TNF and JAK-inhibitor therapy. Breakthrough infections are associated with lower neutralising antibodies and immunosuppressed patients with IBD may receive additional benefit from bivalent vaccine boosters which target Omicron variants.

Funding

Pfizer.

Pre-infection antibody levels of vaccinated healthcare workers with SARS-CoV-2 breakthrough infection: A nested case-control study

AIM

To evaluate anti-RBD IgG antibody levels and neutralizing antibody titers between the health care workers (HCWs) with breakthrough SARS-CoV-2 infection and controls.

METHODS

In this nested case-case control study, we followed 548 vaccinated HCWs with homologous (only with inactivated vaccine) or heterologous (both with inactivated and BNT162b2 vaccine) vaccination for 11 months, prospectively. We obtained blood samples from the participants for quantitative anti-RBD IgG and surrogate neutralization test. The participants with SARS-CoV-2 PCR positivity (at least 14 days after the last vaccination) were considered breakthrough infection. We chose 1:2 matched controls from the cohort, according to age, sex and vaccination status. We used R version 4.0.2 for the statistical analysis.

RESULTS

Sixty-five cases and 130 controls were included in the study. The number of the breakthrough infections in HCWs were correlated with the pandemic waves in Türkiye and peaked during Omicron outbreak. The median age of the cases was 39 and 78.5% were female. The cases had more comorbidities than controls, significantly (p = 0.021). All cases experienced no or mild symptoms and recovered completely. Both pre-infection anti-RBD antibody and neutralizing antibody titers did not differ between cases and matched controls (p = 0.767, p = 0.628).

CONCLUSION

In this study, we showed that there was no comparable difference in humoral response after homologous or heterologous vaccination between the cases of breakthrough infection and matched controls. Compliance with infection control measures should be ensured, in combination with vaccination.

SARS-CoV-2 vaccine breakthrough infection in the older adults: a meta-analysis and systematic review

BACKGROUND

Corona Virus Disease 2019 (COVID-19) mRNA vaccine effectiveness (VE) has recently declined, and reports about COVID-19 breakthrough infection have increased. We aimed to conduct a meta-analysis on population-based studies of the prevalence and incidence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) breakthrough infection amongst older adults worldwide.

METHODS

Studies from PubMed, Embase, Cochrane Library, and Web of Science were systematically screened to determine the prevalence and incidence of SARS-CoV-2 breakthrough infection in older adults from inception to November 2, 2022. Our meta-analysis included 30 studies, all published in English. Pooled estimates were calculated using a random-effect model through the inverse variance method. Publication bias was tested through funnel plots and Egger's regression test, and sensitivity analyses were performed to confirm the robustness of the results. This research was performed following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.

RESULTS

Thirty publications were included in this meta-analysis (17 on prevalence, 17 on incidence, and 4 on both). The pooled prevalence of COVID-19 breakthrough infection among older adults was 7.7 per 1,000 persons (95% confidence interval [95%CI] 4.0-15.0). At the same time, the pooled incidence was 29.1 per 1000 person-years (95%CI 15.2-55.7).

CONCLUSIONS

This meta-analysis provides estimates of prevalence and incidence in older adults. We concluded that the prevalence and incidence of SARS-CoV-19 breakthrough infection in older people was low. The prevalence and incidence of breakthrough infection admitted to hospital, severe-critical, and deathly was significantly lower. Otherwise, there was considerable heterogeneity among estimates in this study, which should be considered when interpreting the results.

Breakthrough mother-to-child transmission of HIV in a low-health facility in Uganda

Objectives

Mother-to-child transmission (MTCT) of HIV can be minimized using elimination of MTCT (eMTCT) services. This study aimed to determine the proportion of infants who tested positive for HIV despite receiving eMTCT services in a rural setting in Northern Uganda.

Methods

We retrospectively reviewed the early infant diagnosis register for the year January 2019 through June 2021 to collect data on participants enrolled in eMTCT services at Lalogi Health Centre IV in Omoro district, Uganda. Breakthrough HIV infection was defined as a positive HIV RNA on a dried blood sample at 18 months in a patient who received eMTCT services as recommended by national guidelines.

Results

A total of 118 infants were enrolled in the study, 64 (54.2%) of whom were female. Most of the participants (n = 111, 94.1%) were on nevirapine prophylaxis for at least 6 weeks, 115 (97.5%) were exclusively breastfed, two (1.7%) were on complementary feeding, and one (0.8%) was not breastfed. Only five (4.2%) infants were lost to follow-up, four (3.4%) had incomplete data, and three (2.5%) had breakthrough HIV infections (positive HIV RNA and HIV antibody tests). All three cases of breakthrough HIV infection (one male and two female infants) were born to mothers who were diagnosed with HIV at delivery and were on nevirapine prophylaxis for less than 6 weeks.

Conclusion

Our findings indicate that while eMTCT services were largely successful in minimizing vertical transmission of HIV in the rural setting in Northern Uganda, there were still some cases of breakthrough HIV infection associated with non-adherence to nevirapine prophylaxis and delayed maternal HIV diagnosis. Therefore, adhering to the national guidelines on nevirapine prophylaxis for at least 6 weeks for children born to mothers with HIV is recommended to further reduce the risk of vertical transmission of HIV.

Reactogenicity, immunogenicity and breakthrough infections following heterologous or fractional second dose COVID-19 vaccination in adolescents (Com-COV3): A randomised controlled trial

BACKGROUND

This was the first study to investigate the reactogenicity and immunogenicity of heterologous or fractional second dose COVID-19 vaccine regimens in adolescents.

METHODS

A phase II, single-blind, multi-centre, randomised-controlled trial recruited across seven UK sites from September to November 2021, with follow-up visits to August 2022. Healthy 12-to-16 years olds were randomised (1:1:1) to either 30 µg BNT162b2 (BNT-30), 10 µg BNT162b2 (BNT-10), or NVX-CoV2373 (NVX), 8 weeks after a first 30 µg dose of BNT162b2. The primary outcome was solicited systemic reactions in the week following vaccination. Secondary outcomes included immunogenicity and safety. 'Breakthrough infection' analyses were exploratory.

FINDINGS

148 participants were recruited (median age 14 years old, 62% female, 26% anti-nucleocapsid IgG seropositive pre-second dose); 132 participants received a second dose. Reactions were mostly mild-to-moderate, with lower rates in BNT-10 recipients. No vaccine-related serious adverse events occurred. Compared to BNT-30, at 28 days post-second dose anti-spike antibody responses were similar for NVX (adjusted geometric mean ratio [aGMR]) 1.09 95% confidence interval (CI): 0.84, 1.42] and lower for BNT-10 (aGMR 0.78 [95% CI: 0.61, 0.99]). For Omicron BA.1 and BA.2, the neutralising antibody titres for BNT-30 at day 28 were similar for BNT-10 (aGMR 1.0 [95% CI: 0.65, 1.54] and 1.02 [95% CI: 0.71, 1.48], respectively), but higher for NVX (aGMR 1.7 [95% CI: 1.07, 2.69] and 1.43 [95% CI: 0.96, 2.12], respectively). Compared to BNT-30, cellular immune responses were greatest for NVX (aGMR 1.73 [95% CI: 0.94, 3.18]), and lowest for BNT-10 (aGMR 0.65 [95% CI: 0.37, 1.15]) at 14 days post-second dose. Cellular responses were similar across the study arms by day 236 post-second dose. Amongst SARS-CoV-2 infection naïve participants, NVX participants had an 89% reduction in risk of self-reported 'breakthrough infection' compared to BNT-30 (adjusted hazard ratio [aHR] 0.11 [95% CI: 0.01, 0.86]) up until day 132 after second dose. BNT-10 recipients were more likely to have a 'breakthrough infection' compared to BNT-30 (aHR 2.14 [95% CI: 1.02, 4.51]) up to day 132 and day 236 post-second dose. Antibody responses at 132 and 236 days after second dose were similar for all vaccine schedules.

INTERPRETATION

Heterologous and fractional dose COVID-19 vaccine schedules in adolescents are safe, well-tolerated and immunogenic. The enhanced performance of the heterologous schedule using NVX-CoV2373 against the Omicron SARS-CoV-2 variant suggests this mRNA prime and protein-subunit boost schedule may provide a greater breadth of protection than the licensed homologous schedule.

FUNDING

National Institute for Health Research and Vaccine Task Force.

TRIAL REGISTRATION

International Standard Randomised Controlled Trial Number registry: 12348322.

A study to assess the severity and risk of COVID-19 breakthrough infection in admitted SARS-CoV-2 vaccinated individual

Background

No vaccine is 100% effective in prevention of infection. The possibility of breakthrough infection of SARS-CoV-2 also cannot be ruled out. So, our study aimed to find out severity and risk of breakthrough infection and find association between epidemiological factors associated with it.

Methodology

A retrospective cross-sectional study was conducted on 148 admitted SARS-CoV-2 vaccinated individual from May 2021 to January 2022 by universal sampling method. A data was collected in the form of socio-demographic, Covid vaccine, clinical details, and outcome of admitted patients. An appropriate statistical test was applied.

Results

Out of the total 148 vaccinated individuals, 66 (44.59%) belongs to 30-59 years of age group and maximum, i.e. 95 (64.19%) were males. 64.86% patients were vaccinated with both doses and 98 (66.26%) individuals were mild cases. Only 8 (5.40%) cases were re-infected with Covid-19 infection. 70.27% individual were comorbid. Out of 148 vaccinated individuals, only 11 (7.43%) individuals were died and among those 7 (63.636%) were comorbid.

Conclusion

Despite being vaccinated, small percentage of people are still getting infected, requires hospitalization, and die because of COVID-19. As far as pandemic continues, continuous genome sequencing and tracking of SARS-CoV-2 is essential and strategies regarding vaccination should be adjusted accordingly.

The rates and symptoms of natural and breakthrough infection pre- and post- Covid-19 non-mRNA vaccination at various peaks amongst Iranian healthcare workers

BACKGROUND/AIMS

The aim of this study was to determine the rate of natural and breakthrough infection and related symptoms of Covid-19 amongst Iranian healthcare workers (HCWs) who were vaccinated by different non-mRNA-based vaccines at peak points.

METHODS

In this cross-sectional study, the RT-PCR test was performed for a total of 10,581 HCWs suspicious of Covid-19 infection. For each HCW, the frequency of SARS-CoV-2 infection and the time of transmission based on vaccination administration time and schedule were examined during different waves of the pandemic. Based on these findings, the study patients were divided into three groups: natural, natural/breakthrough, and breakthrough.

RESULTS

In total, 53% of the HCWs were exposed to SARS-CoV-2 infection between 1 and 5 times within two years after the current pandemic, while 20.7% and 32.3% experienced natural and breakthrough SARS-CoV-2 infection, respectively. Only 6% of the breakthrough-infected HCWs had naturally contracted SARS-CoV-2 infection during the initial waves. The highest natural peaks of infection occurred during the interval administration of the first and second dose of the first vaccination series, while the single highest peak of breakthrough infection belonged to the Omicron wave. It occurred simultaneously with the administration of the third vaccination dose. On the other hand, the highest rate of reinfection was observed amongst people who had received the Sinopharm and Bharat vaccines full-doses.

CONCLUSION

This study compared the clinical differences between the two peaks of Omicron and Delta. This study indicates the rates of natural and breakthrough SARS-CoV-2 infections according to vaccination schedules and different waves of the pandemic.

Breakthrough infections with SARS-CoV-2 omicron efficiently boost antibodies from previous BNT162b2 vaccinations

Objective

To investigate whether SARS-CoV-2 omicron breakthrough infection in individuals after three doses of wildtype-based BNT162b2 increases antibody levels measured by a commercially available wildtype-based immunoassay.

Methods

16 of 21 individuals in a BNT162b2 vaccination cohort (recruited 129 [129-135] days after dose 3) experienced a breakthrough infection (BTI) between March and September 2022. Antibodies to the receptor binding domain (RBP) of the spike protein (Anti-S) were quantified using the wildtype-based Elecsys SARS-CoV-2 S assay (Roche). Antibody responses of triple vaccinated BTI cases were compared to triple vaccinated individuals without breakthrough infection and to 16 matched individuals after primary omicron infection.

Results

In the 16 individuals with primary Omicron infection, the anti-S assay returned only very low results (2.25 [0.61-5.80] U/mL). However, in individuals with BTI, Anti-S levels rose from 7,135 [5,870-17,470] U/mL to 21,705 (7,750-46,137.5) U/mL. At the same time, Anti-S concentrations decreased from 9,120 [7,480-13,480] U/mL to 3,830 (2,390-4,220) U/mL in those 5 of 21 vaccinated only.

Conclusions

Our data suggest that breakthrough infection with omicron can efficiently boost wild-type antibodies in individuals vaccinated with wild-type BNT162b2.

Erratum: Breakthrough infections with the omicron and delta variants of SARS-CoV-2 result in similar re-activation of vaccine-induced immunity

[This corrects the article DOI: 10.3389/fimmu.2022.964525.].

Antibody titres in fully vaccinated healthcare workers with and without breakthrough infection during the Delta and Omicron waves

Introduction

Assessment of antibody response to vaccination against SARS CoV2 has clinical, public health, and policy implications during the pandemic and in the context of future waves.

Method

In this repeated cross-sectional study, we estimated total binding antibody levels to the spike protein of the SARS CoV2 virus post two doses of Covishield vaccine among 133 health care workers (HCWs) (phase 1), followed by antibody levels among a subset (n = 61) of this group at 9 months after the second dose (phase 2). The time period of the first and second blood collection corresponds to Delta and Omicron waves, respectively.

Results

We report 100% seroconversion post 28 days of the second dose of the Covishield vaccine among infection naïve HCWs. In this study, 33% had a breakthrough infection in phase 1 and 24% reported a history of infection in phase 2. The antibody titres were higher in the breakthrough infection group compared to the infection naïve group during both Delta and Omicron waves.

Conclusion

This shows that there is a good seroconversion with two doses of vaccine, weaning of antibody with time, and a rise of antibody titre if infected with SARS CoV 2 subsequently.

The Efficacy of SARS-CoV-2 Vaccination in the Elderly: A Systemic Review and Meta-analysis

BACKGROUND

Given the reduced immune response to vaccines in older populations, this study aimed to evaluate the efficacy of COVID-19 vaccinations and its impact on breakthrough infection, hospital admission, and mortality in the elderly.

METHODS

We carried out a systemic review and meta-analysis where MEDLINE, Web of Science, EMBASE, ClinicalTrials.gov, and Cochrane Central Register for Controlled Trials were queried to identify relevant literature. We included randomized controlled trials (RCTs), non-randomized trials, prospective, observational cohort, and case-control studies assessing breakthrough infection, hospital admission, and mortality after coronavirus 2 (SARS-CoV-2) vaccination in the elderly (≥ 60 years old).

RESULTS

Overall, 26 studies were included in this meta-analysis. Compared with the unvaccinated group, the vaccinated group showed a decreased risk of SARS-CoV-2 infection after 28-34 (relative risk [RR] = 0.42, 95% confidence interval [CI] 0.37-0.49) and 35-60 days (RR = 0.49, 95% CI 0.37-0.62). There was a step-wise increase in efficacy with additional doses with the two-dose group experiencing decreased risk of breakthrough infection (RR = 0.37, 95% CI 0.32-0.42), hospital admissions (RR = 0.25, 95% CI 0.14-0.45), disease severity (RR = 0.38, 95% CI 0.20-0.70), and mortality (RR = 0.21, 95% CI 0.14-0.32) compared with those receiving one or no doses. Similarly three-dose and four-dose vaccine groups also showed a decreased risk of breakthrough infection (3-dose: RR = 0.14, 95% CI 0.10-0.20; 4-dose RR = 0.46, 95% CI 0.4-0.53), hospital admissions (3-dose: RR = 0.11, 95% CI 0.07-0.17; 4-dose: RR = 0.42, 95% CI 0.32-0.55), and all-cause mortality (3-dose: RR = 0.10, 95% CI 0.02-0.48; 4-dose: RR = 0.48, 95% CI 0.28-0.84) Subgroup analysis found that protection against mortality for vaccinated vs. unvaccinated groups was similar by age (60-79 years: RR = 0.59; 95% CI, 0.47-0.74; ≥ 80 years: RR = 0.76; 95% CI, 0.59-0.98) and gender (female: RR = 0.66; 95% CI, 0.50-0.87, male: (RR = 0.58; 95% CI, 0.44-0.76), and comorbid cardiovascular disease (CVD) (RR = 0.69; 95% CI, 0.52-0.92) or diabetes (DM) (RR = 0.59; 95% CI, 0.39-0.89.

CONCLUSIONS

Our pooled results showed that SARS-CoV-2 vaccines administered to the elderly is effective in preventing prevent breakthrough infection, hospitalization, severity, and death. What's more, increasing number of vaccine doses is becoming increasingly effective.

Subjects who developed SARS-CoV-2 specific IgM after vaccination show a longer humoral immunity and a lower frequency of infection

BACKGROUND

We have previously shown that eliciting SARS-CoV-2-specific IgM after vaccination is associated with higher levels of SARS-CoV-2 neutralizing IgG. This study aims to assess whether IgM development is also associated with longer-lasting immunity.

METHODS

We analysed anti-SARS-CoV-2 spike protein IgG and IgM (IgG-S, IgM-S), and anti-nucleocapsid IgG (IgG-N) in 1872 vaccinees at different time points: before the first dose (D1; w0), before the second dose (D2; w3) at three (w6) and 23 weeks (w29) after D2; moreover, 109 subjects were further tested at the booster dose (D3, w44), at 3 weeks (w47) and 6 months (w70) after D3. Two-level linear regression models were used to evaluate the differences in IgG-S levels.

FINDINGS

In subjects who had no evidence of a previous infection at D1 (non-infected, NI), IgM-S development after D1 and D2 was associated with higher IgG-S levels at short (w6, p < 0.0001) and long (w29, p < 0.001) follow-up. Similar IgG-S levels were observed after D3. The majority (28/33, 85%) of the NI subjects who had developed IgM-S in response to vaccination did not experience infection.

INTERPRETATION

The development of anti-SARS-CoV-2 IgM-S following D1 and D2 is associated with higher IgG-S levels. Most individuals who developed IgM-S never became infected, suggesting that IgM elicitation may be associated with a lower risk of infection.

FUNDING

"Fondi Ricerca Corrente" and "Progetto Ricerca Finalizzata" COVID-2020 (Italian Ministry of Health); FUR 2020 Department of Excellence 2018-2022 (MIUR, Italy); the Brain Research Foundation Verona.

Three-dose vaccination-induced immune responses protect against SARS-CoV-2 Omicron BA.2: a population-based study in Hong Kong

Background

The ongoing outbreak of SARS-CoV-2 Omicron BA.2 infections in Hong Kong, the model city of universal masking of the world, has resulted in a major public health crisis. Although the third vaccination resulted in strong boosting of neutralization antibody, vaccine efficacy and correlate of immune protection against the major circulating Omicron BA.2 remain to be investigated.

Methods

We investigated the vaccine efficacy against the Omicron BA.2 breakthrough infection among 470 public servants who had received different SARS-CoV-2 vaccine regimens including two-dose BNT162b2 (2 × BNT, n = 169), three-dose BNT162b2 (3 × BNT, n = 168), two-dose CoronaVac (2 × CorV, n = 34), three-dose CoronaVac (3 × CorV, n = 67) and third-dose BNT162b2 following 2 × CorV (2 × CorV+1BNT, n = 32). Humoral and cellular immune responses after three-dose vaccination were further characterized and correlated with clinical characteristics of BA.2 infection.

Findings

During the BA.2 outbreak, 27.7% vaccinees were infected. The timely third-dose vaccination provided significant protection with lower incidence rates of breakthrough infections (2 × BNT 46.2% vs 3 × BNT 13.1%, p < 0.0001; 2 × CorV 44.1% vs 3 × CorV 19.4%, p = 0.003). Investigation of immune responses on blood samples derived from 90 subjects in three-dose vaccination cohorts collected before the BA.2 outbreak revealed that the third-dose vaccination activated spike (S)-specific memory B cells and Omicron cross-reactive T cell responses, which correlated with reduced frequencies of breakthrough infections and disease severity rather than with types of vaccines. Moreover, the frequency of S-specific activated memory B cells was significantly lower in infected vaccinees than uninfected vaccinees before vaccine-breakthrough infection whereas IFN-γ+ CD4 T cells were negatively associated with age and viral clearance time. Critically, BA.2 breakthrough infection boosted cross-reactive memory B cells with enhanced cross-neutralizing antibodies to Omicron sublineages, including BA.2.12.1 and BA.4/5, in all vaccinees tested.

Interpretation

Our results imply that the timely third vaccination and immune responses are likely required for vaccine-mediated protection against Omicron BA.2 pandemic. Although BA.2 conferred the highest neutralization resistance compared with variants of concern tested before the emergence of BA.2.12.1 and BA.4/5, the third dose vaccination-activated S-specific memory B cells and Omicron cross-reactive T cell responses contributed to reduced frequencies of breakthrough infection and disease severity. Neutralizing antibody potency enhanced by BA.2 breakthrough infection in vaccinees with prior 3 doses of CoronaVac or BNT162b2 may reduce the risk of infection against ongoing BA.2.12.1 and BA.4/5.

Funding

Hong Kong Research Grants Council Collaborative Research Fund, Health and Medical Research Fund, Wellcome Trust, Shenzhen Science and Technology Program, the Health@InnoHK, Innovation and Technology Commission of Hong Kong, China, National Program on Key Research Project, Emergency Key Program of Guangzhou Laboratory, donations from the Friends of Hope Education Fund and the Hong Kong Theme-Based Research Scheme.

Neutralizing antibodies after three doses of the BNT162b2 vaccine, breakthrough infection, and symptoms during the Omicron-predominant wave

OBJECTIVES

To investigate the role of immunogenicity after the third vaccine dose against Omicron infection and COVID-19-compatible symptoms of infection.

METHODS

First, we examined vaccine effectiveness (VE) of the third dose against the second dose during the Omicron wave among the staff at a tertiary hospital in Tokyo. In a case-control study of third vaccine recipients, we compared the preinfection live-virus neutralizing antibodies (NAb) against Omicron between breakthrough cases and their controls who had close contact with patients with COVID-19. Among these cases, we examined the association between NAb levels and the number of COVID-19-compatible symptoms.

RESULTS

Among the 1456 participants for VE analysis, 60 breakthrough infections occurred during the Omicron wave. The third dose VE for infection was 54.6%. Among the third dose recipients, NAb levels against Omicron did not differ between the cases (n = 22) and controls (n = 21). Among the cases, those who experienced COVID-19-compatible symptoms had lower NAb levels against Omicron than those who did not.

CONCLUSION

The third vaccine dose was effective in decreasing the risk of SARS-CoV-2 infection during Omicron wave compared with the second dose. Among third dose recipients, higher preinfection NAb levels may not be associated with a lower risk of Omicron infection. Contrarily, they may be associated with fewer symptoms of infection.

Breakthrough SARS-CoV-2 infections among patients with cancer following two and three doses of COVID-19 mRNA vaccines: a retrospective observational study from the COVID-19 and Cancer Consortium

Background

Breakthrough SARS-CoV-2 infections following vaccination against COVID-19 are of international concern. Patients with cancer have been observed to have worse outcomes associated with COVID-19 during the pandemic. We sought to evaluate the clinical characteristics and outcomes of patients with cancer who developed breakthrough SARS-CoV-2 infections after 2 or 3 doses of mRNA vaccines.

Methods

We evaluated the clinical characteristics of patients with cancer who developed breakthrough infections using data from the multi-institutional COVID-19 and Cancer Consortium (CCC19; NCT04354701). Analysis was restricted to patients with laboratory-confirmed SARS-CoV-2 diagnosed in 2021 or 2022, to allow for a contemporary unvaccinated control population; potential differences were evaluated using a multivariable logistic regression model after inverse probability of treatment weighting to adjust for potential baseline confounding variables. Adjusted odds ratios (aOR) and 95% confidence intervals (CI) are reported. The primary endpoint was 30-day mortality, with key secondary endpoints of hospitalization and ICU and/or mechanical ventilation (ICU/MV).

Findings

The analysis included 2486 patients, of which 564 and 385 had received 2 or 3 doses of an mRNA vaccine prior to infection, respectively. Hematologic malignancies and recent receipt of systemic anti-neoplastic therapy were more frequent among vaccinated patients. Vaccination was associated with improved outcomes: in the primary analysis, 2 doses (aOR: 0.62, 95% CI: 0.44-0.88) and 3 doses (aOR: 0.20, 95% CI: 0.11-0.36) were associated with decreased 30-day mortality. There were similar findings for the key secondary endpoints of ICU/MV (aOR: 0.60, 95% CI: 0.45-0.82 and 0.37, 95% CI: 0.24-0.58) and hospitalization (aOR: 0.60, 95% CI: 0.48-0.75 and 0.35, 95% CI: 0.26-0.46) for 2 and 3 doses, respectively. Importantly, Black patients had higher rates of hospitalization (aOR: 1.47, 95% CI: 1.12-1.92), and Hispanic patients presented with higher rates of ICU/MV (aOR: 1.61, 95% CI: 1.06-2.44).

Interpretation

Vaccination against COVID-19, especially with additional doses, is a fundamental strategy in the prevention of adverse outcomes including death, among patients with cancer.

Funding

This study was partly supported by grants from the National Cancer Institute grant number P30 CA068485 to C-YH, YS, SM, JLW; T32-CA236621 and P30-CA046592 to C.R.F; CTSA 2UL1TR001425-05A1 to TMW-D; ACS/FHI Real-World Data Impact Award, P50 MD017341-01, R21 CA242044-01A1, Susan G. Komen Leadership Grant Hunt to MKA. REDCap is developed and supported by Vanderbilt Institute for Clinical and Translational Research grant support (UL1 TR000445 from NCATS/NIH).

Characteristics of COVID-19 vaccinated and unvaccinated patients admitted to Careggi University Hospital, Florence, Italy

More than 11.5 billion COVID-19 vaccine doses have been administered around the world. Although vaccine effectiveness for severe infections is reported to be 89.0%, breakthrough infections are common and may lead to severe outcome in fragile population. We conducted a real-world observational study on 420 COVID-19 admitted patients from July 2021 to January 2022 in a tertiary level Italian hospital. We collected patient's vaccination and SARS-CoV-2 serological status, SARS-CoV-2 treatments, oxygen supports, intensive (ICU) and subintensive (sub-ICU) care unit admissions, length of staying (LoS) and in-hospital mortality. One-hundred-seventy-two vaccinated and 248 unvaccinated patients were admitted during the study period. Vaccinated group (Vg) had a significantly more elevated Charlson Comorbidity Index than Unvaccinated group (UVg), and no statistical differences were found in terms of in-hospital mortality, LoS or ICU and sub-ICU admissions. Among Vg, anti-S antibodies were detected in 86.18% of patients (seropositives). Vaccinated seronegative patients' in-hospital mortality was significantly higher than vaccinated seropositive patients (33.33% vs 10.69%, p = 0.0055): in particular, mortality rate in 45-69 years old population was higher in vaccinated seronegative group, and comparable in patients ≥ 70 years old. No differences in terms of outcome were registered between Vg and UVg, taking into account that Vg was considerably older and with more comorbidities. In line with other recent observations, higher mortality rate was evidenced for seronegative vaccinated patients. Primary prophylaxis and early treatments result to be necessary, especially for older and immunosuppressed populations.

SARS-CoV-2 vaccine breakthrough infections in Virginia, January 17, 2021 - June 30, 2021

As COVID-19 vaccines moved from the controlled environment of clinical trials to use in real-world settings, it has been important to evaluate vaccine effectiveness. A retrospective cohort study was designed to identify cases of SARS-CoV-2 infection that occurred between January 17-June 30, 2021 in fully vaccinated Virginia residents. Of the fully vaccinated population of Virginia at the end of the study period (N = 4,271,505), 2445 (0.057 %) were reported to have experienced a vaccine breakthrough infection. Of those, 183 (7.5 %) were reported to have been hospitalized for COVID-19 and 53 (2.2 %) died from COVID-19. There were significant differences in vaccine effectiveness over time between both mRNA vaccines and the Janssen vaccine. Increasing age, pre-existing medical conditions, and male sex were associated with severe outcomes (hospitalization or death). Persons at greater risk for severe outcomes should continue to take precautions to prevent SARS-CoV-2 infection, even if fully vaccinated.

Omicron infection increases IgG binding to spike protein of predecessor variants

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission in India in 2020-2022 was driven predominantly by Wild (Wuhan-Hu-1 and D614G), Delta, and Omicron variants. The aim of this study was to examine the effect of infections on the humoral immune response and cross-reactivity to spike proteins of Wuhan-Hu-1, Delta, C.1.2., and Omicron. Residual archival sera (N = 81) received between January 2020 and March 2022 were included. Infection status was inferred by a positive SARS-CoV-2 RT-PCR and/or serology (anti-N and anti-S antibodies) and sequencing of contemporaneous samples (N = 18) to infer lineage. We estimated the levels and cross-reactivity of infection-induced sera including Wild, Delta, Omicron as well as vaccine breakthrough infections (Delta and Omicron). We found an approximately two-fold increase in spike-specific IgG antibody binding in post-Omicron infection compared with the pre-Omicron period, whilst the change in pre- and post-Delta infections were similar. Further investigation of Omicron-specific humoral responses revealed primary Omicron infection as an inducer of cross-reactive antibodies against predecessor variants, in spite of the weaker degree of humoral response compared to Wuhan-Hu-1 and Delta infection. Intriguingly, Omicron vaccine-breakthrough infections when compared with primary infections, exhibited increased humoral responses against RBD (7.7-fold) and Trimeric S (Trimeric form of spike protein) (34.6-fold) in addition to increased binding of IgGs towards previously circulating variants (4.2 - 6.5-fold). Despite Delta breakthrough infections showing a higher level of humoral response against RBD (2.9-fold) and Trimeric S (5.7-fold) compared to primary Delta sera, a demonstrably reduced binding (36%-49%) was observed to Omicron spike protein. Omicron vaccine breakthrough infection results in increased intensity of humoral response and wider breadth of IgG binding to spike proteins of antigenically-distinct, predecessor variants.

Timing of last COVID-19 vaccine dose and SARS-CoV-2 breakthrough infections in fully (boosted) vaccinated healthcare personnel

AIM

To estimate the incidence, timing and severity of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) breakthrough infections in fully vaccinated healthcare personnel (HCP).

METHODS

In total, 6496 fully vaccinated HCP were analysed prospectively from 15^th November 2021 to 17^th April 2022. Full coronavirus disease 2019 (COVID-19) vaccination was defined as a complete primary vaccination series followed by a booster dose at least 6 months later.

RESULTS

Overall, 1845 SARS-CoV-2 breakthrough infections occurred (28.4 episodes per 100 HCP), of which 1493 (80.9%) were COVID-19 cases and 352 (19.1%) were asymptomatic infections. Of the 1493 HCP with COVID-19, four were hospitalized for 3-6 days (hospitalization rate among HCP with COVID-19: 0.3%). No intubations or deaths occurred. SARS-CoV-2 breakthrough infections occurred at a mean of 16.2 weeks after the last vaccine dose. Multi-variable regression analyses showed that among the 1845 HCP with a breakthrough infection, the administration of a COVID-19 vaccine dose ≥16.2 weeks before the infection was associated with increased likelihood of developing COVID-19 rather than asymptomatic SARS-CoV-2 infection [odds ratio (OR) 1.58, 95% confidence interval (CI) 1.01-2.46; P=0.045] compared with administering a vaccine dose later. The likelihood of developing COVID-19 compared with asymptomatic infection increased by 7% weekly after the last COVID-19 vaccine dose (OR 1.07, 95% CI 1.03-1.11; P=0.001).

CONCLUSION

SARS-CoV-2 breakthrough infections are common among fully (boosted) vaccinated HCP. However, full COVID-19 vaccination offered considerable protection against hospitalization. These findings may contribute to defining the optimal timing for booster vaccinations. More efficient COVID-19 vaccines that will also confer protection against SARS-CoV-2 infection are needed urgently.

Durability of Vaccine-Induced and Natural Immunity Against COVID-19: A Narrative Review

Vaccines developed against SARS-CoV-2 have proven to be highly effective in preventing symptomatic infection. Similarly, prior infection with SARS-CoV-2 has been shown to provide substantial protection against reinfection. However, it has become apparent that the protection provided to an individual after either vaccination or infection wanes over time. Waning protection is driven by both waning immunity over time since vaccination or initial infection, and the evolution of new variants of SARS-CoV-2. Both antibody and T/B-cells levels have been investigated as potential correlates of protection post-vaccination or post-infection. The activity of antibodies and T/B-cells provide some potential insight into the underlying causes of waning protection. This review seeks to summarise what is currently known about the waning of protection provided by both vaccination and/or prior infection, as well as the current information on the respective antibody and T/B-cell responses.

COVID-19 severity and vaccine breakthrough infections in idiopathic inflammatory myopathies, other systemic autoimmune and inflammatory diseases, and healthy controls: a multicenter cross-sectional study from the COVID-19 Vaccination in Autoimmune Diseases (COVAD) survey

OBJECTIVES

We aimed to compare the spectrum and severity of COVID-19 and vaccine breakthrough infections (BIs) among patients with IIMs, other systemic autoimmune and inflammatory diseases (SAIDs), and healthy controls (HCs).

METHODS

This is a cross-sectional study with data from the COVAD study, a self-reported online global survey that collected demographics, COVID-19 history, and vaccination details from April to September 2021. Adult patients with at least one COVID-19 vaccine dose were included. BIs were defined as infections occurring > 2 weeks after any dose of vaccine. Characteristics associated with BI were analyzed with a multivariate regression analysis.

RESULTS

Among 10,900 respondents [42 (30-55) years, 74%-females, 45%-Caucasians] HCs were (47%), SAIDs (42%) and IIMs (11%). Patients with IIMs reported fewer COVID-19 cases before vaccination (6.2%-IIM vs 10.5%-SAIDs vs 14.6%-HC; OR = 0.6, 95% CI 0.4-0.8, and OR = 0.3, 95% CI 0.2-0.5, respectively). BIs were uncommon (1.4%-IIM; 1.9%-SAIDs; 3.2%-HC) and occurred in 17 IIM patients, 13 of whom were on immunosuppressants, and 3(18%) required hospitalization. All-cause hospitalization was higher in patients with IIM compared to HCs [23 (30%) vs 59 (8%), OR = 2.5, 95% CI 1.2-5.1 before vaccination, and 3 (18%) vs 9 (5%), OR = 2.6, 95% CI 1.3-5.3 in BI]. In a multivariate regression analysis, age 30-60 years was associated with a lower odds of BI (OR = 0.7, 95% CI 0.5-1.0), while the use of immunosuppressants had a higher odds of BI (OR = 1.6, 95% CI 1.1-2.7).

CONCLUSIONS

Patients with IIMs reported fewer COVID-19 cases than HCs and other SAIDs, but had higher odds of all-cause hospitalization from COVID-19 than HCs. BIs were associated with the use of immunosuppressants and were uncommon in IIMs.

Neutralization sensitivity, fusogenicity, and infectivity of Omicron subvariants

BACKGROUND

The emergence of SARS-CoV-2 Omicron subvariants has raised questions regarding resistance to immunity by natural infection or immunization. We examined the sensitivity of Delta and Omicron subvariants (BA.1, BA.1.1, BA.2, BA.2.12.1, BA.4/5, and BA.3) to neutralizing antibodies from BBIBP-CorV-vaccinated and BBIBP-CorV- or ZF2001-boosted individuals, as well as individuals with Delta and BA.1 breakthrough infections, and determined their fusogenicity and infectivity.

METHODS

In this cross-sectional study, serum samples from two doses of BBIBP-CorV-vaccinated individuals 1 (n = 36), 3 (n = 36), and 7 (n = 37) months after the second dose; BBIBP-CorV- (n = 25) or ZF2001-boosted (n = 30) individuals; and fully vaccinated individuals with Delta (n = 30) or BA.1 (n = 26) infection were collected. The serum-neutralizing reactivity and potency of bebtelovimab were assessed against D614G, Delta, and Omicron subvariants (BA.1, BA.1.1, BA.2, BA.2.12.1, BA.4/5, and BA.3) through a pseudovirus neutralization assay. The fusogenicity and infectivity of D614G, Delta, and Omicron subvariants were determined by cell-cell fusion assay and pseudovirus infection assay, respectively.

RESULTS

Omicron subvariants markedly escaped vaccine-elicited neutralizing antibodies after two doses of BBIBP-CorV with comparable efficiency. A third dose vaccination of BBIBP-CorV or ZF2001 increased neutralizing antibody titers and breadth against Delta and three Omicron subvariants. Delta and BA.1 breakthrough infections induced comparable neutralizing antibody titers against D614G and Delta variants, whereas BA.1 breakthrough infections elicited a stronger and broader antibody response against three Omicron subvariants than Delta breakthrough infections. BA.2.12.1 and BA.4/5 are more resistant to immunity induced by breakthrough infections. Bebtelovimab had no significant loss of potency against the Delta and Omicron subvariants. Cell culture experiments showed Omicron subvariants to be less fusogenic and have higher infectivity than D614G and Delta with comparable efficiency.

CONCLUSIONS

These findings have important public health implications and highlight the importance of repeated exposure to SARS-CoV-2 antigens to broaden the neutralizing antibody response against Omicron subvariants.

Impact of vaccination on the presence and severity of symptoms in hospitalized patients with an infection of the Omicron variant (B.1.1.529) of the SARS-CoV-2 (subvariant BA.1)

OBJECTIVES

The emergence of SARS-CoV-2 variants raised questions about the extent to which vaccines designed in 2020 have remained effective. We aimed to assess whether vaccine status was associated with the severity of Omicron SARS-CoV-2 infection in hospitalized patients.

METHODS

We conducted an international, multi-centric, retrospective study in 14 centres (Bulgaria, Croatia, France, and Turkey). We collected data on patients hospitalized for ≥24 hours between 1 December 2021 and 3 March 2022 with PCR-confirmed infection at a time of exclusive Omicron circulation and hospitalization related or not related to the infection. Patients who had received prophylaxis by monoclonal antibodies were excluded. Patients were considered fully vaccinated if they had received at least two injections of either mRNA and/or ChAdOx1-S or one injection of Ad26.CoV2-S vaccines.

RESULTS

Among 1215 patients (median age, 73.0 years; interquartile range, 57.0-84.0; 51.3% men), 746 (61.4%) were fully vaccinated. In multivariate analysis, being vaccinated was associated with lower 28-day mortality (Odds Ratio [95% Confidence Interval] (OR [95CI]) = 0.50 [0.32-0.77]), intensive care unit admission (OR [95CI] = 0.40 [0.26-0.62]), and oxygen requirement (OR [95CI] = 0.34 [0.25-0.46]), independent of age and comorbidities. When co-analysing these patients with Omicron infection with 948 patients with Delta infection from a study we recently conducted, Omicron infection was associated with lower 28-day mortality (OR [95CI] = 0.53 [0.37-0.76]), intensive care unit admission (OR [95CI] = 0.19 [0.12-0.28]), and oxygen requirements (OR [95CI] = 0.50 [0.38-0.67]), independent of age, comorbidities, and vaccination status.

DISCUSSION

Originally designed vaccines have remained effective on the severity of Omicron SARS-CoV-2 infection. Omicron is associated with a lower risk of severe forms, independent of vaccination and patient characteristics.

SARS-CoV-2 Breakthrough Infection after mRNA-1273 Booster among CoronaVac-Vaccinated Healthcare Workers

It remains unknown whether the Indonesian healthcare workers (HCWs) who had received two doses of CoronaVac vaccine and one dose of mRNA-1273 booster could be protected during the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron wave. In total, 125 infection-naïve and 10 previously infected HCWs were recruited. The mRNA-1273 booster substantially increased titer of anti-SARS-CoV-2 spike protein receptor-binding domain antibodies. However, the monitoring revealed that 34 out of 125 infection-naïve (27.2%) and 3 out of 10 previously infected HCWs (30.0%) were infected during the Omicron wave. All infected HCWs were either asymptomatic or having mild coronavirus disease 2019 (COVID-19) and subsequently fully recovered, supporting the heterologous prime-boost strategy against COVID-19.

Assessment of antibody responses against SARS-CoV-2 in unvaccinated individuals and vaccinees from Omicron-BA.2 infection in Zhaoqing, Guangdong Province, China

Currently, the majority of the global population has been vaccinated with the COVID-19 vaccine, and characterization studies of antibodies in vivo from Omicron breakthrough infection and naive infection populations are urgently needed to provide pivotal clues about accurate diagnosis, treatment, and next-generation vaccine design against SARS-CoV-2 infection. We showed that after infection with Omicron-BA.2, the antibody levels of specific IgM against the Wuhan strain and specific IgG against Omicron were not significantly elevated within 27 days of onset. Interestingly, in this study, the levels of humoral immunity against Omicron-specific IgM were significantly increased after breakthrough infection, suggesting that the detection of Omicron-specific IgM antibodies can be used as a test criterion of Omicron breakthrough infection. In addition, we observed that serums from unvaccinated individuals and the majority of vaccinated infections possessed only low or no neutralizing activity against Omicron at the onset of Omicron breakthrough infections, and at the later stage of Omicron-BA.2 breakthrough infection, levels of neutralization antibody against the Wuhan and Omicron strains were elevated in infected individuals. The findings of this study provide important clues for the diagnosis of Omicron breakthrough infections, antibody characterization studies and vaccine design against COVID-19.

Demographics and Clinical Characteristics of COVID-19-vaccinated Patients Admitted to ICU: A Multicenter Cohort Study from India (PostCoVac Study-COVID Group)

Background

Emergency authorization and approval were given for the coronavirus disease-19 (COVID-19) vaccines. The efficacy reported after phase III trials were 70.4% and 78% for Covishield and Covaxin, respectively.In this study, we aim to analyze the risk factors, which were associated with mortality in critically ill COVID-19-vaccinated patients admitted into intensive care unit (ICU).

Materials and methods

This study was conducted from April 1, 2021 to December 31, 2021 across five centers in India. Patients who had received either one or two doses of any of the COVID vaccines and developed COVID-19 were included. The ICU mortality was a primary outcome.

Results

A total of 174 patients with COVID-19 illness were included in the study. The mean age was 57 years standard deviation (SD 15). Acute physiology, age and chronic health evaluation (APACHE II) score and the sequential organ failure assessment (SOFA) score were 14 (8-24.5) and 6 (4-8), respectively. Multiple variable logistic regression showed patients who have received a single dose [odds ratio (OR): 2.89, confidence interval (CI): 1.18, 7.08], neutrophil:lymphocyte (NL) ratio (OR: 1.07, CI: 1.02,1.11), and SOFA score (OR: 1.18, CI: 1.03,1.36) were associated with higher mortality.

Conclusion

The mortality in the vaccinated patients admitted to the ICU was 43.68% due to COVID illness. The mortality was lower in patients who had received two doses.

How to cite this article

Havaldar AA, Prakash J, Kumar S, Sheshala K, Chennabasappa A, Thomas RR et al. Demographics and Clinical Characteristics of COVID-19-vaccinated Patients Admitted to ICU: A Multicenter Cohort Study from India (PostCoVac Study-COVID Group). Indian J Crit Care Med 2022;26(11):1184-1191.

Protective Effect of Neonatal Hepatitis B Vaccine Against HBV Breakthrough Infection in Children with Leukemia: A Real-world Study

BACKGROUND AND AIMS

Hepatitis B vaccine is the most effective preventive measure against hepatitis B virus (HBV) infection. However, the risk of HBV breakthrough infection in fully immunized children (neonatal hepatitis B immunization) who receive immunosuppressive therapy and transfusion of blood components is not well characterized. In this real-world study, we aimed to investigate the immune protection conferred by neonatal hepatitis B vaccine in children with acute lymphoblastic leukemia (ALL) who were treated with immunosuppressive therapy and blood component transfusions.

METHODS

Children with ALL who had received all three doses of neonatal hepatitis B vaccine were included in this study. HBV seromarkers were detected before and after the initiation of immunosuppressive therapy.

RESULTS

A total of 1,011 children with ALL who were fully vaccinated against hepatitis B in infancy before the initiation of immunosuppressive therapy were eligible for inclusion. HBV infection was detected in four of 410 children (0.98%) with an HBsAg test after the initiation of immunosuppressive therapy. The median interval from treatment initiation was 19 months.

CONCLUSIONS

Three doses of neonatal hepatitis B vaccine conferred adequate protection. In endemic regions, there is a low risk of HBV breakthrough infection in fully immunized children with immunosuppressive therapy.