Seric IgG anti-SARS-CoV-2 pre- and post- Covid-19 pandemic from Mexican asymptomatic subjects.

OBJECTIVE: To detect serum IgG anti-SARS-CoV-2 in pre-and post- Covid-19 pandemic in Mexican asymptomatic subjects in order to know the degree of viral dispersion. MATERIALS AND METHODS: Association of serum IgG antibodies (determined by ELISA) to sociodemographic and clinical data or contact with Covid-19 cases in three groups of subjects: 1) Covid-19 pre-pandemic blood donors (n= 538); 2) Covid-19 post-pandemic blood donors (n= 243); 3) Covid-19 post-pandemic neurological patients (n= 312). None of the subjects studied had been vaccinated. RESULTS: The positive rate of IgG anti-SARS-CoV-2 was notably higher in participants recruited during the pandemic (donors, 29.6%; neurological patients, 15.7%) than in those recruited pre-pan-demic (donors 0.6%) (p <0.001). Other conditions associated to antibody positivity were being a worker in sales or services, or having had previous contact with people with Covid-19, for donnors and neurological patients, and having diabetes mellitus, for neurological patients. Higher positivity levels of anti-SARS-CoV-2 IgG were found in females than in males. The highest proportion of subjects with anti-SARS-CoV-2 antibodies was found in central Mexico. CONCLUSIONS: The dispersion of SARS-CoV-2 in asymptomatic, unvaccinated subjects (donors and neurological patients) recruited in a Mexican health institution, who work in sales or services or had previously had contact with Covid-19 patients is 16 to 30%. The level of positivity for anti-SARS-CoV-2 IgG is higher in females than in males. SARS-CoV-2 antibody seropreva-lence follow-up studies must be favored among the general population, being mandatory for donors.

Seric IgG anti-SARS-CoV-2 pre- and post- Covid-19 pandemic from Mexican asymptomatic subjects / IgG sérica anti-SARS-CoV-2 pre y post pandemia de Covid-19 en mexicanos asintomáticos

Abstract: Objective: To detect serum IgG anti-SARS-CoV-2 in pre- and post- Covid-19 pandemic in Mexican asymptomatic subjects in order to know the degree of viral dispersion. Materials and methods: Association of serum IgG antibodies (determined by ELISA) to sociodemographic and clinical data or contact with Covid-19 cases in three groups of subjects: 1) Covid-19 pre-pandemic blood donors (n= 538); 2) Covid-19 post-pandemic blood donors (n= 243); 3) Covid-19 post-pandemic neurological patients (n= 312). None of the subjects studied had been vaccinated. Results: The positive rate of IgG anti-SARS-CoV-2 was notably higher in participants recruited during the pandemic (donors, 29.6%; neurological patients, 15.7%) than in those recruited pre-pandemic (donors 0.6%) (p <0.001). Other conditions associated to antibody positivity were being a worker in sales or services, or having had previous contact with people with Covid-19, for donnors and neurological patients, and having diabetes mellitus, for neurological patients. Higher positivity levels of anti-SARS-CoV-2 IgG were found in females than in males. The highest proportion of subjects with anti-SARS-CoV-2 antibodies was found in central Mexico. Conclusions: The dispersion of SARS-CoV-2 in asymptomatic, unvaccinated subjects (donors and neurological patients) recruited in a Mexican health institution, who work in sales or services or had previously had contact with Covid-19 patients is 16 to 30%. The level of positivity for anti-SARS-CoV-2 IgG is higher in females than in males. SARS-CoV-2 antibody seroprevalence follow-up studies must be favored among the general population, being mandatory for donors.

Resumen: Objetivo: Detectar IgG sérica anti-SARS-CoV-2 antes y después de la pandemia de Covid-19 en sujetos mexicanos asintomáticos, con la intención de conocer el grado de dispersión viral. Material y métodos: Se analizó la asociación de anticuerpos IgG séricos (determinados por ELISA), datos sociodemográficos y clínicos y contacto con casos de Covid-19 en tres grupos de sujetos: 1) donadores de sangre reclutados antes de la pandemia de Covid-19 (n= 538); 2) donadores (n= 243) y 3) pacientes neurológicos (n= 312) reclutados durante la pandemia de Covid-19. Ninguno de los sujetos estudiados había sido vacunado. Resultados: La tasa de positividad de IgG anti-SARS-CoV-2 fue notablemente mayor en los participantes reclutados durante la pandemia (donadores, 29.6%; pacientes neurológicos, 15.7%) que en los reclutados prepandemia (donadores 0.6%). Otras condiciones asociadas con positividad de anticuerpos fueron trabajar en ventas o servicios, o haber tenido contacto previo con pacientes Covid-19, en donadores y pacientes neurológicos, y haber tenido diabetes mellitus, en pacientes neurológicos. Se encontraron mayores niveles de positividad de IgG anti-SARS-CoV-2 en mujeres que en hombres. La mayor proporción de sujetos con anticuerpos anti-SARS-CoV-2 procedía del centro de México. Conclusiones: La dispersión del SARS-CoV-2 en sujetos asintomáticos, no vacunados (donadores y pacientes neurológicos), reclutados en una institución de salud mexicana, que trabajan en ventas o servicios, o tienen contacto previo con pacientes Covid-19 es de 16 a 30%. El nivel de positividad de IgG anti-SARS-CoV-2 es más alto en mujeres que en hombres. Los estudios de seguimiento de la seroprevalencia del SARS-CoV-2 deben favorecerse en la población general, siendo obligatorios en los donadores.