Anti-Spike IgG against COVID-19 three months after the end of the pandemic in Northeast of Portugal

• Autor(es): Duro, Inês ; Manso , Maria Conceição ; Couto, Cristina ; Duro, Mary
• Data: 2024
• Origem: Scientific Letters
• Assunto(s): COVID-19; Reinfection; Vaccine efficacy; Booster
• Tipo de Documento: Artigo científico
• Idioma: Inglês

Descrição

The emergence of new COVID-19 strains and variants and immune escape from vaccines forces reflection on the need to continue vaccinating the entire population. This study intends to monitor and understand the reinfection in recently vaccinated people. The amount of anti-Spike IgG, the number of vaccine doses, and infections/reinfections in 82 volunteers, three months after the declaration of the end of the COVID-19 pandemic, was evaluated. All participants, asymptomatic at the time, presented IgG, including those who had no infection or vaccination (n = 3). Those vaccinated showed high levels of antibodies, even 36 months after the last booster. There was no significant difference in the immunological status with the type of vaccine, age, and sex, although women and older people had higher median IgG values. A significant positive correlation was observed between vaccine doses and IgG (rs = 0.373; p < 0.001). Women vaccinated before coming into contact with the virus showed higher antibody levels (16607 vs. 6233; p = 0.012). This study suggests women’s immune systems are more effective at fighting the virus. It also supports the effectiveness of vaccines on the humoral response. However, the timing of infections is inconsistent with the expected immunity. Therefore, continuation of booster doses is questionable except for immunocompromised patients.