No abstract

In this large cohort of healthcare workers, we aimed to estimate the rate of reinfections by SARS-CoV-2 over 2 years of the COVID-19 pandemic. We investigated the proportion of reinfections among all the cases of SARS-CoV-2 infection from March 10, 2020 until March 10, 2022. Reinfection was defined as the appearance of new symptoms that on medical evaluation were suggestive of COVID-19 and confirmed by a positive RT-PCR. Symptoms had to occur more than 90 days after the previous infection. These 2 years were divided into time periods based on the different variants of concern (VOC) in the city of São Paulo. There were 37,729 medical consultations due to COVID-19 at the hospital’s Health Workers Services; and 25,750 RT-PCR assays were performed, of which 23% (n = 5865) were positive. Reinfection by SARS-CoV-2 was identified in 5% (n = 284) of symptomatic cases. Most cases of reinfection occurred during the Omicron period (n = 251; 88%), representing a significant increase on the SARS-CoV-2 reinfection rate before and during the Omicron variant period (0.8% vs. 4.3%; p < 0.001). The mean interval between SARS-CoV-2 infections was 429 days (ranged from 122 to 674). The Omicron variant spread faster than Gamma and Delta variant. All SARS-CoV-2 reinfections were mild cases.

Brazil has approximately 180 million inhabitants, of whom 15.2 million are aged 60 and older and 1.9 million are aged 80 and older. By 2025, the Brazilian elderly population is expected to grow to more than 32 million. Brazil has many problems related to its geographic and population size. Great distances between major cities, marked cultural and racial heterogeneity between the various geographic regions, high poverty levels, and decreasing family size all combine to put pressure on the medical and social services that can be made available to the elder population. Less than 500 Brazilian physicians are certified as geriatricians, translating into one geriatrician for every 37,000 elderly Brazilians. Beside 15 geriatric medicine residencies a larger number of fellowship programs exist, and these programs are in high demand, with more than 20 candidates per position, indicating new opportunities for growth in elder care. In addition, geriatric initiatives such as the annual elder vaccination program and the elder statute, recently approved by the Brazilian Congress, indicate that geriatric care in Brazil is entering a new era of growth and development. Although the challenges remain great, there are opportunities for Brazilian geriatrics and gerontology.

Background: CoronaVac, a vaccine containing inactivated SARS-CoV-2, demonstrated efficacy of 50.39% 14 days or more after the 2nd dose. The objective of this study is to report the occurrence of symptomatic COVID-19 in a cohort of HCW vaccinated with CoronaVac and to estimate its effectiveness. Methods: CoronaVac was given to HCWs in Hospital das Clinicas on 18-21 January, 2021 (epi week 3) (22,402 HCWs), and on 14-16 February, 2021 (epi week 7) (21,652 HCWs). Weekly cases of symptomatic COVID-19 were evaluated. Using the period from 2020 epi week 24 through 2021 epi week 2 (before vaccination), a Poisson regression was fit to model the HCWs with COVID-19 of the hospital, and the officially reported cases in the city of Sao Paulo. The predicted numbers of cases among HCWs for 2021 epi weeks 3-12 were then compared to the observed numbers of cases (after vaccination). Effectiveness was estimated for weeks 9-12 (2 to 5 weeks after the 2nd dose). 142 samples after vaccination were evaluated for SARS-CoV-2 variants of concern. Results: Since the 1st dose there were 380 HCW diagnosed with COVID-19. On visual analysis, the number of cases of COVID-19 in the city increased sharply in 2021. The number of cases among the HCW did not follow. The estimated effectiveness 2 and 3 weeks after 2nd dose was 50.7% and 51.8%, respectively, and increased over the next 2 weeks. 67/142 samples (47%) were variants of concern, mostly P1 (57). Conclusion: Coronavac is effective in preventing COVID-19.

As with many other developing countries, Brazil faces the rapid aging of its population over few decades. Unlike what happened in developed northern hemisphere countries, Brazilians are getting older before the country in general, and elders in particular become richer. With an area of 8.5 million km 2 (world 5 th largest), Brazil has a population of 190 million inhabitants (2010 census) with 20.6 million above 60 years, nearly three million above 80 years.1 By 2025 the senior population is expected to top 32 million, as illustrated in Figure 1. The life expectancy at birth is now 67.3 years for men and 75.2 years for women.