There is considerable interest in the waning of effectiveness of coronavirus disease 2019 (COVID-19) vaccines and vaccine effectiveness (VE) of booster doses. Using linked national Brazilian databases, we undertook a test-negative design study involving almost 14 million people (~16 million tests) to estimate VE of CoronaVac over time and VE of BNT162b2 booster vaccination against RT–PCR-confirmed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and severe COVID-19 outcomes (hospitalization or death). Compared with unvaccinated individuals, CoronaVac VE at 14–30 d after the second dose was 55.0% (95% confidence interval (CI): 54.3–55.7) against confirmed infection and 82.1% (95% CI: 81.4–82.8) against severe outcomes. VE decreased to 34.7% (95% CI: 33.1–36.2) against infection and 72.5% (95% CI: 70.9–74.0) against severe outcomes over 180 d after the second dose. A BNT162b2 booster, 6 months after the second dose of CoronaVac, improved VE against infection to 92.7% (95% CI: 91.0−94.0) and VE against severe outcomes to 97.3% (95% CI: 96.1−98.1) 14–30 d after the booster. Compared with younger age groups, individuals 80 years of age or older had lower protection after the second dose but similar protection after the booster. Our findings support a BNT162b2 booster vaccine dose after two doses of CoronaVac, particularly for the elderly.

Long COVID has received less attention from the scientific community than acute COVID-19, representing less than 2% of COVID-19 publications in PubMed Clinical Queries (as of August 31, 2022). Consequently, several important aspects remain undefined, such as its prevalence. Long COVID has been reported to affect between 7.5% to 89% of patients [1–4]. However, most […]

To date, no information has been published on the effectiveness of inactivated whole-virus COVID-19 vaccines plus heterologous booster against symptomatic infection and severe outcomes (hospitalization or death) during the dominance of the SARS-CoV-2 Omicron variant period. We evaluated the vaccine effectiveness (VE) of CoronaVac plus BNT162b2 booster during the period of dominance of the Omicron variant in Brazil (January to April 2022). Using a test-negative design, we analysed data for 2,471,576 individuals tested during the Omicron variant’s dominant period using a nationally linked database from Brazil. Compared to unvaccinated, vaccinees maintained protection against severe outcomes, with an estimated VE of 84.1% (95% CI:83.2–84.9) at more than 120 days after BNT162b2 booster. Furthermore, while we detected a high level of protection against severe outcomes for individuals up to 79 years old, waning was observed for individuals aged ≥80 years, with VE decreasing from 81.3% (95% CI:77.9–84.2) at 31–60 days to 72.9% (95% CI:70.6–75.1) at 120 days or more after the booster dose. However, no significant protection against symptomatic infection was observed at this time period. In conclusion, except for individuals aged ≥80 years, CoronaVac plus a BNT162b2 booster dose offered high and durable protection against severe outcomes due to Omicron.

Chikungunya virus (CHIKV) has caused worldwide epidemics that impose a major burden on health systems. Approximately half of infected individuals develop chronic debilitating arthralgia, affecting their quality of life. Here, we identified the relevant clinical and demographic variables in the acute phase of CHIKV infection prospectively linked to chronic arthralgia to elaborate a prognostic scoring system. Acute CHIKV infection cases (n = 134) confirmed by serology or molecular test were examined <10 days of disease onset and followed for one year to evaluate for disease progression. Potential risk factors for chronic arthralgia were evaluated by multivariate analysis to develop a prognostic scoring system, which was subsequently tested in an independent validation cohort consisting of 42 individuals. A total of 107 out of 134 (80%) acute CHIKV-confirmed cases from the derivation cohort were re-examined one year after enrollment. Chronic arthralgia post-CHIKV infection was diagnosed in 64 (60%). Five of the 12 parameters evaluated in the acute phase were statistically associated with persistent arthralgia and were further tested by Bayesian analysis. These variables were weighted to yield a prognosis score denominated SHERA (Sex, Hypertension, Edema, Retroocular pain, Age), which exhibited 81.3% accuracy in predicting long-term arthralgia post-CHIKV infection in the derivation cohort, and 76.5% accuracy in the validation cohort. The simplified and externally validated prognostic scoring system, SHERA, is a useful method to screen acutely CHIKV-infected patients at elevated risk of chronic arthralgia who will benefit from specific interventions. This tool could guide public health policies, particularly in resource-constrained settings. Debilitating articular pain frequently occurs as a consequence of Chikungunya virus infection, affecting individuals' quality of life for a long time. Here we present a simple tool to predict people at risk to remain with long-term articular pain after Chikungunya infection. We evaluated 134 patients acutely affected by Chikungunya virus searching for characteristics previously described as related to persistent symptoms. We examined about 80% of those individuals after one year to identify those with persistent arthralgia. We detected five features that represent good predictors and developed a scoring system named SHERA (www.sheracalculator.com/shera), the acronyms of Sex (female), Hypertension, Edema, Retroocular pain and Age (>26y). SHERA can correctly predict 8 out of every 10 Chikungunya infected individuals that will persist with articular pain symptoms at least one year after disease onset. These results were confirmed in the second group of patients from another city affected by Chikungunya outbreak. The easy-to-use scoring system can be applied in areas with limited access to health support, helping to identify the ones who will need special care and benefit from early intervention.

In 2015, during the outbreak of Zika virus (ZIKV) in Brazil, we identified 3 cases of acute hearing loss after exanthematous illness. Serology yielded finding compatible with ZIKV as the cause of a confirmed (n = 1) and a probable (n = 2) flavivirus infection, indicating an association between ZIKV infection and transient hearing loss.