SARS-CoV-2 Reinfection Is a New Challenge for the Effectiveness of Global Vaccination Campaign: A Systematic Review of Cases Reported in Literature

COVID-19 Reinfection Has Better Outcomes Than the First Infection in Solid Organ Transplant Recipients

BACKGROUND

Solid organ transplant recipients face an increased risk of severe coronavirus disease 2019 (COVID-19) and are vulnerable to repeat severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections. In nonimmunocompromised individuals, SARS-CoV-2 reinfections are milder likely because of cross-protective immunity. We sought to determine whether SARS-CoV-2 reinfection exhibits milder manifestations than primary infection in transplant recipients.

METHODS

Using a large, prospective cohort of adult transplant patients with COVID-19, we identified patients with SARS-CoV-2 reinfections. We performed a 1:1 nearest neighbor propensity score matching to control potential confounders, including the COVID-19 variant. We compared outcomes including oxygen requirement, hospitalization, and intensive care unit admission within 30 d after diagnosis between patients with reinfection and those with the first episode of COVID-19.

RESULTS

Between 2020 and 2023, 103 reinfections were identified in a cohort of 1869 transplant recipients infected with SARS-CoV-2 (incidence of 2.7% per year). These included 50 kidney (48.5%), 27 lung (26.2%), 7 heart (6.8%), 6 liver (5.8%), and 13 multiorgan (12.6%) transplants. The median age was 54.5 y (interquartile range [IQR], 40.5-65.5) and the median time from transplant to first infection was 6.6 y (IQR, 2.8-11.2). The time between the primary COVID-19 and reinfection was 326 d (IQR, 226-434). Three doses or more of SARS-CoV-2 vaccine are received by 87.4% of patients. After propensity score matching, reinfections were associated with significantly lower hospitalization (5.8% versus 19.4%; risk ratio, 0.3; 95% CI, 0.12-0.71) and oxygen requirement (3.9% versus 13.6%; risk ratio, 0.29; 95% CI, 0.10-0.84). In a within-patient analysis only in the reinfection group, the second infection was milder than the first (3.9% required oxygen versus 19.4%, P  < 0.0001), and severe first COVID-19 was the only predictor of severe reinfection.

CONCLUSIONS

Transplant recipients with COVID-19 reinfection present better outcomes than those with the first infection, providing clinical evidence for the development of cross-protective immunity.

Impact on the time elapsed since SARS-CoV-2 infection, vaccination history, and number of doses, on protection against reinfection

SARS-CoV-2 reinfections have been frequent, even among those vaccinated. The aim of this study is to know if hybrid immunity (infection + vaccination) is affected by the moment of vaccination and number of doses received. We conducted a retrospective study in 746 patients with a history of COVID-19 reinfection and recovered the dates of infection and reinfection and vaccination status (date and number of doses). To assess differences in the time to reinfection(tRI) between unvaccinated, vaccinated before 6 months, and later; and comparing one, two or three doses (incomplete, complete and booster regime) we performed the log-rank test of the cumulative incidence calculated as 1 minus the Kaplan-Meier estimator. Also, an adjusted Cox-regression was performed to evaluate the risk of reinfection in all groups. The tRI was significantly higher in those vaccinated vs. non-vaccinated (p < 0.001). However, an early incomplete regime protects similar time than not receiving a vaccine. Vaccination before 6 months after infection showed a lower tRI compared to those vaccinated later with the same regime (adj-p < 0.001). Actually, early vaccination with complete and booster regimes provided lower length of protection compared to vaccinating later with incomplete and complete regime, respectively. Vaccination with complete and booster regimes significantly increases the tRI (adj-p < 0.001). Vaccination increases the time it takes for a person to become reinfected with SARS-CoV-2. Increasing the time from infection to vaccination increases the time in which a person could be reinfected and reduces the risk of reinfection, especially in complete and booster regimes. Those results emphasize the role of vaccines and boosters during the pandemic and can guide strategies on future vaccination policy.

Evidence of SARS-CoV-2 reinfection: analysis of 35,000 subjects and overview of systematic reviews

BACKGROUND

Reinfection by SARS-CoV-2 is a rare but possible event. We evaluated the prevalence of reinfections in the Province of Modena and performed an overview of systematic reviews to summarize the current knowledge.

METHODS

We applied big data analysis and retrospectively analysed the results of oro- or naso-pharyngeal swab results tested for molecular research of viral RNA of SARS-CoV-2 between 1 January 2021 and 30 June 2021 at a single center. We selected individuals with samples sequence of positive, negative and then positive results. Between first and second positive result we considered a time interval of 90 days to be sure of a reinfection. We also performed a search for and evaluation of systematic reviews reporting SARS-CoV-2 reinfection rates. Main information was collected and the methodological quality of each review was assessed, according to A Measurement Tool to Assess systematic Reviews (AMSTAR).

RESULTS

Initial positive results were revealed in more than 35,000 (20%) subjects; most (28%) were aged 30-49 years old. Reinfection was reported in 1,258 (3.5%); most (33%) were aged 30-49 years old. Reinfection rates according to vaccinated or non-vaccinated subjects were 0.6% vs 1.1% (p < 0.0001). Nine systematic reviews were identified and confirmed that SARS-CoV-2 reinfection rate is a rare event. AMSTAR revealed very low-moderate levels of quality among selected systematic reviews.

CONCLUSIONS

There is a real, albeit rare risk of SARS-CoV-2 reinfection. Big data analysis enabled accurate estimates of the reinfection rates. Nevertheless, a standardized approach to identify and report reinfection cases should be developed.

Genomic evolution of the SARS-CoV-2 Variants of Concern: COVID-19 pandemic waves in India

SARS-CoV-2 has mutated rapidly since its first case report in Wuhan, China, leading to the emergence of an indefinite number of variants. India has witnessed three waves of the COVID-19 pandemic. The country saw its first wave of SARS-CoV-2 illness from late January 2020 to February 2021. With a peak surge of cases in mid-September 2020, India recorded more than 11 million cases and a death toll of more than 0.165 million at this time. India faced a brutal second wave driven by the emergence of highly infectious SARS-CoV-2 variants B.1.617.2 (Delta variant) and the third wave with the leading cause of BA.2 (Omicron variant), which has led to an unprecedented rise in COVID-19 cases in the country. On September 14, 2022, India recorded a cumulative 44.51 million cases of COVID-19 with more than 0.528 million deaths. The discovery of common circulating mutants is facilitated by genome sequencing. The changes in the Spike surface glycoprotein recombinant binding domains served as the critical alterations, resulting in enhanced infectivity and transmissibility, with severe clinical effects. Further, the predominant mutation in the SARS-CoV-2 spike protein; the D614G strains served as a model for vaccine development. The mutation of the Wuhan strain to the Variant of Concern led to a significant increase in SARS-CoV-2 infections. In addition, there was a shift in the age group affected by SARS-CoV-2 variant infection. The current review summarized the COVID-19 pandemic's Variant of Concern and the advent of SARS-CoV-2 in India.

SARS-CoV-2 reinfections: Overview of efficacy and duration of natural and hybrid immunity

Seroprevalence surveys suggest that more than a third and possibly more than half of the global population has been infected with SARS-CoV-2 by early 2022. As large numbers of people continue to be infected, the efficacy and duration of natural immunity in terms of protection against SARS-CoV-2 reinfections and severe disease is of crucial significance for the future. This narrative review provides an overview on epidemiological studies addressing this issue. National surveys covering 2020-2021 documented that a previous SARS-CoV-2 infection is associated with a significantly reduced risk of reinfections with efficacy lasting for at least one year and only relatively moderate waning immunity. Importantly, natural immunity showed roughly similar effect sizes regarding protection against reinfection across different SARS-CoV-2 variants, with the exception of the Omicron variant for which data are just emerging before final conclusions can be drawn. Risk of hospitalizations and deaths was also reduced in SARS-CoV-2 reinfections versus primary infections. Observational studies indicate that natural immunity may offer equal or greater protection against SARS-CoV-2 infections compared to individuals receiving two doses of an mRNA vaccine, but data are not fully consistent. The combination of a previous SARS-CoV-2 infection and a respective vaccination, termed hybrid immunity, seems to confer the greatest protection against SARS-CoV-2 infections, but several knowledge gaps remain regarding this issue. Natural immunity should be considered for public health policy regarding SARS-CoV-2.

Impact of the Omicron variant on SARS-CoV-2 reinfections in France, March 2021 to February 2022

Since the first reports in summer 2020, SARS-CoV-2 reinfections have raised concerns about the immunogenicity of the virus, which will affect SARS-CoV-2 epidemiology and possibly the burden of COVID-19 on our societies in the future. This study provides data on the frequency and characteristics of possible reinfections, using the French national COVID-19 testing database. The Omicron variant had a large impact on the frequency of possible reinfections in France, which represented 3.8% of all confirmed COVID-19 cases since December 2021.

A multitope SARS-COV-2 vaccine provides long-lasting B cell and T cell immunity against Delta and Omicron variants

Background

The Delta and Omicron variants of SARS-CoV-2 are currently responsible for breakthrough infections due to waning immunity. We report phase I/II trial results of UB-612, a multitope subunit vaccine containing S1-RBD-sFc protein and rationally designed promiscuous peptides representing sarbecovirus conserved helper T cell and cytotoxic T lymphocyte epitopes on the nucleocapsid (N), membrane (M), and spike (S2) proteins.

Method

We conducted a phase I primary 2-dose (28 days apart) trial of 10, 30, or 100 μg UB-612 in 60 healthy young adults 20 to 55 years old, and 50 of them were boosted with 100 μg of UB-612 approximately 7 to 9 months after the second dose. A separate placebo-controlled and randomized phase II study was conducted with 2 doses of 100 μg of UB-612 (n = 3,875, 18–85 years old). We evaluated interim safety and immunogenicity of phase I until 14 days after the third (booster) dose and of phase II until 28 days after the second dose.

Results

No vaccine-related serious adverse events were recorded. The most common solicited adverse events were injection site pain and fatigue, mostly mild and transient. In both trials, UB-612 elicited respective neutralizing antibody titers similar to a panel of human convalescent sera. The most striking findings were long-lasting virus-neutralizing antibodies and broad T cell immunity against SARS-CoV-2 variants of concern (VoCs), including Delta and Omicron, and a strong booster-recalled memory immunity with high cross-reactive neutralizing titers against the Delta and Omicron VoCs.

Conclusion

UB-612 has presented a favorable safety profile, potent booster effect against VoCs, and long-lasting B and broad T cell immunity that warrants further development for both primary immunization and heterologous boosting of other COVID-19 vaccines.

Trial Registration

ClinicalTrials.gov: NCT04545749, NCT04773067, and NCT04967742.

Funding

UBI Asia, Vaxxinity Inc., and Taiwan Centers for Disease Control, Ministry of Health and Welfare.

The Moderating Effect of Resilience on Mental Health Deterioration among COVID-19 Survivors in a Mexican Sample

Resilience has been reported to be a protective psychological variable of mental health; however, little is known about its role in COVID-19 survivors. Thus, in this study, we aimed to evaluate the levels of depression, anxiety, stress, traumatic impact, and resilience associated with COVID-19, as well as to investigate the role of resilience as a moderating variable. A sample of 253 participants responded to an online survey; all were previously diagnosed with COVID-19 by a nasopharyngeal swab RT-PCR test, were older than 18 years, and signed an informed consent form. Significant negative correlations were found between resilience and the mental health variables. Higher resilience was significantly related to a lower impact of the event, stress, anxiety, and depression when the number of symptoms was low. Only when the duration of COVID-19 was short and resilience levels were medium or high was psychological distress reduced. Moreover, resilience moderated the effects of COVID-19 on mental health, even if a relapse occurred. The results emphasize the need for interdisciplinary interventions aimed at providing COVID-19 patients with psychological and social resources to cope with the disease, as well as with probable relapses.

SARS-CoV-2 Variants and Clinical Outcomes: A Systematic Review

Background: From the start of the COVID-19 pandemic, new SARS-CoV-2 variants have emerged that potentially affect transmissibility, severity, and immune evasion in infected individuals. In the present systematic review, the impact of different SARS-CoV-2 variants on clinical outcomes is analyzed. Methods: A systematic review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020. Two databases (PubMed and ScienceDirect) were searched for original articles published from 1 January 2020 to 23 November 2021. The articles that met the selection criteria were appraised according to the Newcastle–Ottawa Quality Assessment Scale. Results: Thirty-three articles were included, involving a total of 253,209 patients and 188,944 partial or complete SARS-CoV-2 sequences. The most reported SARS-CoV-2 variants showed changes in the spike protein, N protein, RdRp and NSP3. In 28 scenarios, SARS-CoV-2 variants were found to be associated with a mild to severe or even fatal clinical outcome, 15 articles reported such association to be statistically significant. Adjustments in eight of them were made for age, sex and other covariates. Conclusions: SARS-CoV-2 variants can potentially have an impact on clinical outcomes; future studies focused on this topic should consider several covariates that influence the clinical course of the disease.