Adverse events following immunization of elderly with COVID-19 inactivated virus vaccine (CoronaVac) in Southeastern Brazil: an active surveillance study.

Healthcare workers, the elderly and other vulnerable populations were the first to receive COVID-19 vaccines in public health programs. There were few vaccine safety data available on the elderly. This observational study aimed to evaluate the inactivated vaccine (CoronaVac) safety in the elderly, at the beginning of the vaccination program, in Sao Paulo city, Brazil. The elderly people that received CoronaVac at the Reference Center for Special Immunobiologicals (CRIE) or at home, administered by the Interdisciplinary Home Care Team (NADI) of the Hospital das Clinicas were invited to participate in this phase 4 observational study. The vaccination schedule included two CoronaVac doses 28 days apart. The information on solicited and unsolicited adverse events following immunization were collected by phone calls on days 4 and 8 after each vaccine dose. We enrolled 158 adults aged 65 to 101 years (mean of 84.1 years); 63.9% were females and 95.6% had chronic conditions, 21.5% had moderate or severe impairment in daily living activities; 34.2% were pre-frail and 19.6% were frail. We were able to contact 95.6% and 91.6% of the vaccinated people, after the first and second doses, respectively; 31.8% and 23.4% of the contacted participants reported some adverse events (AE) following the first and second doses, respectively. Pain at the injection site, fatigue, myalgia and headaches were the most frequent solicited AE. Most AE were mild to moderate. There were eight severe adverse events, but none of them were considered related to the vaccine. The CoronaVac was safe and well tolerated by these adults of advanced age with frailty and comorbidities.

Time-dependent contraction of the SARS-CoV-2-specific T-cell responses in convalescent individuals.

Background: Adaptive immunity in severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection is decisive for disease control. Delayed activation of T cells is associated with a worse outcome in coronavirus disease 2019 (COVID-19). Although convalescent individuals exhibit solid T-cell immunity, to date, long-term immunity to SARS-CoV-2 is still under investigation. Objectives: We aimed to characterize the specific T-cell response on the basis of the in vitro recall of IFN-γ-producing cells to in silico-predicted peptides in samples from SARS-CoV-2 convalescent individuals. Methods: The sequence of the SARS-CoV-2 genome was screened, leading to the identification of specific and promiscuous peptides predicted to be recognized by CD4+ and CD8+ T cells. Next, we performed an in vitro recall of specific T cells from PBMC samples from the participants. The results were analyzed according to clinical features of the cohort and HLA diversity. Results: Our results indicated heterogeneous T-cell responsiveness among the participants. Compared with patients who exhibited mild symptoms, hospitalized patients had a significantly higher magnitude of response. In addition, male and older patients showed a lower number of IFN-γ-producing cells. Analysis of samples collected after 180 days revealed a reduction in the number of specific circulating IFN-γ-producing T cells, suggesting decreased immunity against viral peptides. Conclusion: Our data are evidence that in silico-predicted peptides are highly recognized by T cells from convalescent individuals, suggesting a possible application for vaccine design. However, the number of specific T cells decreases 180 days after infection, which might be associated with reduced protection against reinfection over time.

Deciphering Multifactorial Correlations of COVID-19 Incidence and Mortality in the Brazilian Amazon Basin.

Amazonas suffered greatly during the COVID-19 pandemic. The mortality and fatality rates soared and scarcity of oxygen and healthcare supplies led the health system and funerary services to collapse. Thus, we analyzed the trends of incidence, mortality, and lethality indicators of COVID-19 and the dynamics of their main determinants in the state of Amazonas from March 2020 to June 2021. This is a time-series ecological study. We calculated the lethality, mortality, and incidence rates with official and public data from the Health Department. We used the Prais-Winsten regression and trends were classified as stationary, increasing, or decreasing. The effective reproduction number (Rt) was also estimated. Differences were considered significant when p < 0.05. We extracted 396,772 cases of and 13,420 deaths from COVID-19; 66% of deaths were in people aged over 60; 57% were men. Cardiovascular diseases were the most common comorbidity (28.84%), followed by diabetes (25.35%). Rural areas reported 53% of the total cases and 31% of the total deaths. The impact of COVID-19 in the Amazon is not limited to the direct effects of the pandemic itself; it may present characteristics of a syndemic due to the interaction of COVID-19 with pre-existing illnesses, endemic diseases, and social vulnerabilities.

A promiscuous T cell epitope-based HIV vaccine providing redundant population coverage of the HLA class II elicits broad, polyfunctional T cell responses in nonhuman primates.

Over the last few decades, several emerging or reemerging viral diseases with no readily available vaccines have ravaged the world. A platform to fastly generate vaccines inducing potent and durable neutralizing antibody and T cell responses is sorely needed. Bioinformatically identified epitope-based vaccines can focus on immunodominant T cell epitopes and induce more potent immune responses than a whole antigen vaccine and may be deployed more rapidly and less costly than whole-gene vaccines. Increasing evidence has shown the importance of the CD4+ T cell response in protection against HIV and other viral infections. The previously described DNA vaccine HIVBr18 encodes 18 conserved, promiscuous epitopes binding to multiple HLA-DR-binding HIV epitopes amply recognized by HIV-1-infected patients. HIVBr18 elicited broad, polyfunctional, and durable CD4+and CD8+ T cell responses in BALB/c and mice transgenic to HLA class II alleles, showing cross-species promiscuity. To fully delineate the promiscuity of the HLA class II vaccine epitopes, we assessed their binding to 34 human class II (HLA-DR, DQ, and -DP) molecules, and immunized nonhuman primates. Results ascertained redundant 100% coverage of the human population for multiple peptides. We then immunized Rhesus macaques with HIVBr18 under in vivo electroporation. The immunization induced strong, predominantly polyfunctional CD4+ T cell responses in all animals to 13 out of the 18 epitopes; T cells from each animal recognized 7-11 epitopes. Our results provide a preliminary proof of concept that immunization with a vaccine encoding epitopes with high and redundant coverage of the human population can elicit potent T cell responses to multiple epitopes, across species and MHC barriers. This approach may facilitate the rapid deployment of immunogens eliciting cellular immunity against emerging infectious diseases, such as COVID-19.