SARS-CoV-2 mRNA Vaccine Breakthrough Infections in Fully Vaccinated Healthcare Personnel: A Systematic Review

Glucose control during breakthrough SARS-CoV-2 infections in vaccinated patients with type 1 diabetes

AIMS

This study aims at evaluating the trend of glycemic control metrics during the infection of SARS-CoV-2 in individuals with Type 1 Diabetes (T1D) using a Continuous Glucose Monitoring (CGM) system and vaccinated against COVID-19.

MATERIALS AND METHODS

This is a retrospective study of T1D subjects who got a breakthrough SARS-CoV-2 infection between November 2021 and February 2022. Data of glycemic control of CGM-derived metrics were compared 14 days before COVID-19 (Time 1), 14 days during COVID-19 (Time 2) and 14 days after COVID-19 (Time 3).

RESULTS

A total of 106 patients with T1D and breakthrough SARS-CoV-2 infection was included in the analysis. A significant reduction of GMI [%, 7.41 ± 1.60 vs 7.52 ± 1.63, P = 0.006)] and increase of TIR [%, 54.6 ± 20.4 vs 52.1 ± 19.7, P = 0.026] were observed at Time 3 as compared with Time 2. There was a significant reduction of SD (P < 0.001) and CV (P < 0.001) at Time 3 and Time 2 as compared with Time 1, associated with significant changes of mean glucose levels, TBR level 1 and total daily insulin doses.

CONCLUSIONS

Breakthrough SARS-CoV-2 infection did not worsen glycemic control in vaccinated people with T1D.

The Prospective COVID-19 Post-Immunization Serological Cohort in Munich (KoCo-Impf): Risk Factors and Determinants of Immune Response in Healthcare Workers

Antibody studies analyze immune responses to SARS-CoV-2 vaccination and infection, which is crucial for selecting vaccination strategies. In the KoCo-Impf study, conducted between 16 June and 16 December 2021, 6088 participants aged 18 and above from Munich were recruited to monitor antibodies, particularly in healthcare workers (HCWs) at higher risk of infection. Roche Elecsys^® Anti-SARS-CoV-2 assays on dried blood spots were used to detect prior infections (anti-Nucleocapsid antibodies) and to indicate combinations of vaccinations/infections (anti-Spike antibodies). The anti-Spike seroprevalence was 94.7%, whereas, for anti-Nucleocapsid, it was only 6.9%. HCW status and contact with SARS-CoV-2-positive individuals were identified as infection risk factors, while vaccination and current smoking were associated with reduced risk. Older age correlated with higher anti-Nucleocapsid antibody levels, while vaccination and current smoking decreased the response. Vaccination alone or combined with infection led to higher anti-Spike antibody levels. Increasing time since the second vaccination, advancing age, and current smoking reduced the anti-Spike response. The cumulative number of cases in Munich affected the anti-Spike response over time but had no impact on anti-Nucleocapsid antibody development/seropositivity. Due to the significantly higher infection risk faced by HCWs and the limited number of significant risk factors, it is suggested that all HCWs require protection regardless of individual traits.

SARS-CoV-2 Vaccine Breakthrough Infections of Omicron and Delta Variants in Healthcare Workers

Understanding SARS-CoV-2 breakthrough infections in vaccinated healthcare workers is of key importance in mitigating the effects of the COVID-19 pandemic in healthcare facilities. An observational prospective cohort study was conducted in vaccinated employees with acute SARS-CoV-2 infection between October 2021 and February 2022. Serological and molecular testing was performed to determine SARS-CoV-2 viral load, lineage, antibody levels, and neutralizing antibody titers. A total of 571 (9.7%) employees experienced SARS-CoV-2 breakthrough infections during the enrolment period, of which 81 were included. The majority (n = 79, 97.5%) were symptomatic and most (n = 75, 92.6%) showed Ct values < 30 in RT-PCR assays. Twenty-four (30%) remained PCR-positive for > 15 days. Neutralizing antibody titers were strongest for the wildtype, intermediate for Delta, and lowest for Omicron variants. Omicron infections occurred at higher anti-RBD-IgG serum levels (p = 0.00001) and showed a trend for higher viral loads (p = 0.14, median Ct difference 4.3, 95% CI [-2.5-10.5]). For both variants, viral loads were significantly higher in participants with lower anti-RBD-IgG serum levels (p = 0.02). In conclusion, while the clinical course of infection with both the Omicron and Delta variants was predominantly mild to moderate in our study population, waning immune response over time and prolonged viral shedding were observed.

COVID-19 vaccination refusal and suspension of work among healthy healthcare personnel in Italy: A cross-sectional study of their knowledge and attitudes toward vaccinations

Despite the initial optimistic projections from various countries and the evidence that vaccination against coronavirus disease 2019 (COVID-19) reduces the associated hospitalization rates and mortality, vaccine hesitancy and refusal among healthcare personnel (HCP) became a major public health concern globally. The aim of this survey was to estimate the knowledge about the Italian Vaccination Plan for HCP and attitudes about occupational vaccinations for HCP among Italian HCP who refused COVID-19 vaccination and were suspended from work. A total of 52 HCP participated in the study. Nurses were the prevalent profession among vaccination refusers. About COVID-19, 24 (26.2%) of all responders have been involved in COVID-19 care and 21 (40.4%) had a history of COVID-19. None had received influenza and pneumococcus vaccination in the past. Knowledge of vaccinations recommended for HCP was high, ranging from 75% to 98% by vaccine. Instead, all HCP were against any mandatory vaccination policy for all HCP. Finally, most HCP questioned the expected benefits and safety of vaccines in general, raised issues of mistrust of information provided for authorities and of compliance with their HCP' vaccination recommendations. Our study indicates good knowledge of occupational vaccinations but strong anti-vaccination beliefs among Italian HCP who refused COVID-19 vaccination and were suspended from work.

Neutralizing Antibodies as Predictors of Vaccine Breakthrough Infection in Healthcare Workers Vaccinated with or without a Heterologous Booster Dose: A Cohort Study during the Third COVID-19 Wave in Peru

We evaluated neutralizing antibody (NAbs) levels as a protective factor against vaccine breakthrough infection (VBI) in healthcare workers (HCWs) during the third COVID-19 wave in Peru. This retrospective cohort study employed the information from a private laboratory in Lima (Peru) of HCW who received only two BBIBP-CorV vaccines or (additionally) a heterologous booster with BNT162b2. We evaluated the association between the VBI and the levels of NAbs at 21, 90, 180, and 210 days after the BBIBP-CorV second dose. NAbs were calculated with the cPass™ SARS-CoV-2 Neutralization Antibody Detection kit (surrogate virus neutralization test (sVNT)) and the Elecsys^® anti-SARS-CoV-2 S Test. Of the 435 HCW evaluated, 31.72% had an infection previous to vaccination, 68.28% received a booster dose, and 23.21% had a VBI during the third wave. The variables associated with a lower risk of VBI were male sex (aRR: 0.43) and those who had (180 days after BBIBP-CorV inoculation) NAbs levels ≥ 60% (aRR: 0.58) and ≥90% (aRR: 0.59) on cPass™, and ≥500 with Elecsys^® (aRR: 0.58). HCW whose NAbs persisted at higher levels six months after the BBIBP-CorV showed a lower risk of suffering from a VBI during the third COVID-19 wave.

COVID-19: Current Status and Future Prospects

This second Special Issue in a series of Special Issues in Tropical Medicine and Infectious Disease looks at recent global research on the current Coronavirus (COVID-19) Pandemic [...].

SARS-CoV-2 infection among healthcare workers whom already received booster vaccination during epidemic outbreak of omicron variant in Taiwan

BACKGROUND/PURPOSE

Healthcare workers (HCWs) are at risk of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection due to occupational exposure. We aim to investigate the prevalence and risk factors of SARS-CoV-2 infection among HCWs during epidemic outbreak of omicron variant in Taiwan.

METHODS

Sequential reserved serum samples collected from our previous study during December 2021 and July 2022 were tested for antibodies against SARS-CoV-2 nucleocapsid protein (NP). Diagnosis of SARS-CoV-2 infection was defined as positive either of anti-SARS-CoV-2 nucleoprotein, rapid antigen test or polymerase chain reaction. Retrospective chart review and a questionnaire were used to access the symptoms and risk factors for SARS-CoV-2 infection.

RESULTS

Totally 300 participants (69.3% female) with a median age of 37.9 years were enrolled. A significant increase incidence of SARS-CoV-2 infection was found before and during community outbreak (11.91 versus 230.93 per 100,000 person-days, P < 0.001), which was a trend paralleling that observed in the general population. For 61 SARS-CoV-2 infected participants, nine (14.8%) were asymptomatic. Multivariate analysis revealed recent contact with a SARS-CoV-2 infected household (odds ratio [OR], 7.01; 95% confidence interval [95% CI], 3.70-13.30; P < 0.001) and co-existed underlying autoimmune diseases (OR, 4.46; 95% CI, 1.28-15.51; P = 0.019) were significant risk factors associated with acquisition of SARS-CoV-2 infection among HCWs.

CONCLUSION

Community factors, such as closely contact with SARS-CoV-2 infected individuals and underlying immune suppression status, were significant factors for acquisition of SARS-CoV-2 infection among HCWs. We suggest the application of appropriate infection control measures for HCWs should be maintained to reduce risk of SARS-CoV-2 infection.

COVID-19 breakthrough infections and humoral immune response among BNT162b2 vaccinated healthcare workers in Malaysia

The evaluation of breakthrough infection and humoral immunity responses are important outcomes for vaccination policy for healthcare staff. This prospective cohort study collected blood samples at 5-time points; before primary vaccine doses, and at 2, 10 and 24 weeks after BNT162b2 vaccination from 551 HCWs, between March and October 2021. We investigated the association between anti-spike-1 protein receptor-binding domain (anti-S1-RBD) antibody geometric mean titre (GMT) and breakthrough infections. Two weeks post-vaccination, the GMT of anti-S1-RBD antibodies was measured at almost maximum detectable value (3115 BAU/ml [95% CI, 3051-3180]); it decreased to 1486 BAU/ml (95% CI, 1371-1610) at 10 weeks; and to 315 BAU/ml (95% CI, 283-349) at 24 weeks. Prior COVID-19 infection and age significantly affected the antibody titres. Fifty-six participants, none of whom were COVID-19 convalescents, had breakthrough infections between 10 and 24 weeks post-vaccination. Before breakthrough infections, the GMT was not different between the breakthrough and non-breakthrough individuals. After infection, the GMT was significantly higher in individuals with breakthrough infections (2038 BAU/ml [95%CI, 1547-2685]), specifically in symptomatic breakthroughs, compared to those without infection (254 BAU/ml [95%CI, 233-278]). A notable surge in breakthrough infections among healthcare workers coincided with the emergence of the Delta variant and when BNT162b2-elicited antibody responses waned in 10-24 weeks (i.e. approximately 3-6 months). Post-breakthrough, the antibody response was boosted in individuals with symptomatic presentations, but not asymptomatic individuals. The study finding supports administering booster vaccination for healthcare staff, including those who recovered from asymptomatic breakthrough infection.

Towards novel nano-based vaccine platforms for SARS-CoV-2 and its variants of concern: Advances, challenges and limitations

Vaccination is the most effective tool available for fighting the spread of COVID-19. Recently, emerging variants of SARS-CoV-2 have led to growing concerns about increased transmissibility and decreased vaccine effectiveness. Currently, many vaccines are approved for emergency use and more are under development. This review highlights the ongoing advances in the design and development of different nano-based vaccine platforms. The challenges, limitations, and ethical consideration imposed by these nanocarriers are also discussed. Further, the effectiveness of the leading vaccine candidates against all SARS-CoV-2 variants of concern are highlighted. The review also focuses on the possibility of using an alternative non-invasive routes of vaccine administration using micro and nanotechnologies to enhance vaccination compliance and coverage.

Neutralizing antibody responses in healthcare personnel after three doses of mRNA BNT162b2 vaccine and association with baseline characteristics and past SARS-CoV-2 infection

Aim

To estimate neutralizing antibody (NAb) immunity against SARS-CoV-2 in 739 healthcare personnel (HCP) vaccinated with three doses of BNT162b2 mRNA vaccine.

Methods

Serum samples were collected at 3, 6, and 9 months after the second vaccine dose and at 7–55 days after the third dose. Samples were tested for NAbs against SARS-CoV-2 receptor binding domain.

Results

The mean inhibition rates at 3, 6, and 9 months after the second dose were 86.33%, 73.38%, and 61.18%, and increased to 95.57% after the booster dose. Younger HCP and HCP with past SARS-CoV-2 infection had higher inhibition rates while there was an inverse correlation between NAb levels and comorbidities or tobacco use (p-values < 0.001). Increased NAb titers were also noticed in women (p-value = 0.033), especially at the end of the 9-month study period.

Conclusion

NAb levels increased considerably after a booster mRNA vaccine dose. Host factors and past SARS-CoV-2 infection influence NAb titers.

Factors Associated With COVID-19 Breakthrough Infections in Large Midwestern Healthcare System: Implications for Vulnerable Healthcare Personnel

OBJECTIVE

The aim of the study is to identify factors associated with breakthrough infection among a cohort of Midwestern healthcare personnel (HCP).

METHODS

SARS-CoV-2-positive test results between March 1, 2020, and July 31, 2021, were collected from electronic medical records of HCP to identify breakthrough infections.

RESULTS

Healthcare personnel who were younger than 35 years, received the Pfizer vaccine, and worked in COVID clinical units had greater adjusted odds of breakthrough infection. COVID infection before full vaccination was associated with reduced odds of breakthrough infection.

CONCLUSIONS

Our study concluded that the most vulnerable HCP are younger, working in COVID-19 clinical units, and received Pfizer-BioNTech primary series vaccines. Healthcare personnel who had COVID before vaccination were at reduced risk of breakthrough infection, indicating that supplemental immunity could better protect at-risk HCP groups.

Early and Longitudinal Humoral Response to the SARS-CoV-2 mRNA BNT162b2 Vaccine in Healthcare Workers: Significance of BMI, Adipose Tissue and Muscle Mass on Long-Lasting Post-Vaccinal Immunity

BACKGROUND

This study aimed to investigate the early and longitudinal humoral response in Healthcare Workers (HCWs) after two doses of the BNT162b2 vaccine and to assess the association between metabolic and anthropometric parameters and the humoral response after vaccination.

METHODS

The study included 243 fully vaccinated HCWs: 25.50% previously infected with SARS-CoV-2 (with prior history of COVID-19-PH) and 74.40%-uninfected, seronegative before the first vaccination (with no prior history of COVID-19-NPH). IgG antibodies were measured, and sera were collected: prior to the vaccination, 21 days after the first dose, and 14 days and 8 months after the second dose.

RESULTS

21 days after the first dose, 90.95% of individuals were seropositive; 14 days after the second dose, persistent immunity was observed in 99.18% HCWs, 8 months after complete vaccination-in 61.73%. Statistical analysis revealed that HCWs with PH had a greater chance of maintaining a humoral response beyond eight months after vaccination. Increased muscle mass, decreased fat mass, and younger age may positively affect long-term immunity. Smokers have a reduced chance of developing immunity compared to non-smokers.

CONCLUSIONS

Fully vaccinated HCWs with PH are more likely to be seropositive than fully inoculated volunteers with NPH.

The Italian Version of the Adult Vaccine Hesitancy Scale (aVHS) for the Working-Age Population: Cross-Cultural Adaptation, Reliability, and Validity

The adult Vaccine Hesitancy Scale (aVHS) is valid and reliable for evaluating attitudes toward vaccine preventable diseases (VPDs). The aim of the present study was to evaluate the cross-cultural adaptation, reliability, and validity of the Italian version of the aVHS. After cross-cultural adaptation of the aVHS, internal consistency (IC), intra-class correlation (ICC), and content validity (S-CVI) were evaluated through a survey on 160 workers. Results of the ICC were analyzed on questionnaires administered twice at a distance of two months and revealed a satisfactory reproducibility (0.87). The IC of the aVHS was assessed by the Cronbach alpha coefficient test, with a result of 0.94, demonstrating an excellent IC reliability. The S-CVI calculated for the total scale was 0.97. The aVHS is a valid and reliable tool for evaluating vaccine hesitancy toward adult vaccinations. We suggest the use of this scale in upcoming surveys on opinions and perceptions of adult vaccinations.