Seroprevalencia de anticuerpos frente al SARS-CoV-2 en la Comunidad Valenciana (España) en octubre de 2022 Seroprevalence of antibodies against SARS-CoV-2 in the Valencian Community (Spain) as of October 2022

Objetivo: Estimar la seroprevalencia de anticuerpos frente al SARS-CoV-2 en la Comunidad Valenciana (España) en octubre de 2022, cuando BA.5 era la variante predominante. Método: Estudio transversal de base poblacional de ámbito autonómico en 88 centros de atención primaria de la Comunidad Valenciana seleccionados aleatoriamente. Resultados: La seroprevalencia de anticuerpos antinucleocápside (indicativos de infección previa) y frente al dominio de la unión al receptor (indicativos de infección o vacunación) fue del 71,0% (intervalo de confianza [IC]: 67,8-74,2) y del 98,4% (IC: 97,5-99,3), respectivamente. El 66,7% (IC: 63,4-70,0) de la población mostraba inmunidad híbrida, pero solo el 43,2% de los mayores de 80 años. Conclusiones: La alta proporción de inmunidad híbrida detectada era relevante para las estrategias de salud pública, pero era aconsejable un segundo refuerzo de vacunación en la población anciana.

Seroprevalence of antibodies against SARS-CoV-2 in the Valencian Community (Spain) as of October 2022.

OBJECTIVE: To estimate the seroprevalence of SARS-CoV-2 antibodies in the Valencian Community (Spain) in October 2022, when BA.5 was the predominant variant. METHOD: Cross-sectional, region-wide, population-based serosurvey study in 88 randomly selected primary care centers of the Valencian Community. RESULTS: Seroprevalence of anti-nucleocapsid (indicative of past infection) and total receptor binding domain (indicative of past infection or vaccination) antibodies was 71.0% (confidence interval [CI]: 67.8-74.2) and 98.4% (CI: 97.5-99.3), respectively. 66.7% (CI: 63.4-70.0) of the population shows hybrid immunity, but only 43.2% in those 80 and over. CONCLUSIONS: The high proportion of hybrid immunity detected is relevant for public health strategies. A second vaccination booster was advisable in the elderly population.

Side effects during the week after first dose vaccination with four Covid-19 vaccines. Results of the ProVaVac Survey Study with 13,837 people in Spain.

BACKGROUND: In 2021, four vaccines against Covid-19 (BNT162b2, mRNA-1273, ChAdOx1nCoV-19, and JNJ-78436735) were employed in the region of Valencia, Spain. We conducted a survey to identify real-world, self-reported frequency and severity of side effects during the week after vaccination. METHODS: Survey data was obtained from April 19, 2021, to October 6, 2021, at three different moments in time: day one, day three and day seven after vaccination. Answers were linked to individual-level, personal and clinical information. Respondents were stratified by the vaccine they received and reported effects were presented over time and stratified by severity. We compared our results per vaccine with the frequencies stated in each Summary of Product Characteristics (SmPC). We used binomial logistic models to identify associations between respondent characteristics and side effects. RESULTS: No symptoms were reported by 1,986 respondents (14.35 %), 6,254 informed exclusively mild symptoms (45.20 %), 3,444 up to moderate symptoms (24.89 %), and 2,153 people (15.56 %) notified also severe symptoms. Among the latter, the more frequent were extreme tiredness (7.0 %), and nausea or vomiting (7.1 %). The reported frequency of facial paralysis (0.4 %) was much higher than reflected in SmPCs. Female sex, younger age, previous positive Active Infection Diagnostic Test, chronicity, and vaccination with other than the BNT162b2 vaccine were associated to an increased risk of side effects (p < 0.001). CONCLUSIONS: Side effects after vaccination are common in the real-world. However, they are principally mild, and their frequency declines after a few days. Providing patients with dependable, beforehand information about side effects may improve outcomes and reinforce vaccination programs.