Résumé
ABSTRACT The global reemergence of measles in 2018-2019 reinforces the relevance of high-coverage immunization to maintain the disease elimination. During an outbreak in the Sao Paulo State in 2019, several measles cases were reported in individuals who were adequately vaccinated according to the current immunization schedule recommends. This study aimed to assess measles IgG antibody seropositivity and titers in previously vaccinated adults. A cross-sectional study was conducted at CRIE-HC-FMUSP (Sao Paulo, Brazil) in 2019. It included healthy adults who had received two or more Measles-Mumps-Rubella vaccines (MMR) and excluded individuals with immunocompromising conditions. Measles IgG antibodies were measured and compared by ELISA (Euroimmun®) and chemiluminescence (LIASON®). The association of seropositivity and titers with variables of interest (age, sex, profession, previous measles, number of measles-containing vaccine doses, interval between MMR doses, and time elapsed since the last MMR dose) was analyzed. A total of 162 participants were evaluated, predominantly young (median age 30 years), women (69.8%) and healthcare professionals (61.7%). The median interval between MMR doses was 13.2 years, and the median time since the last dose was 10.4 years. The seropositivity rate was 32.7% by ELISA and 75.3% by CLIA, and a strong positive correlation was found between the tests. Multivariate analyses revealed that age and time since the last dose were independently associated with positivity. Despite being a single-center evaluation, our results suggest that measles seropositivity may be lower than expected in adequately immunized adults. Seropositivity was higher among older individuals and those with a shorter time since the last MMR vaccine dose.
Résumé
ABSTRACT 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.