Immune profile of healthcare professionals six months after vaccination or exposure to SARS‐CoV‐2 in Angola

Abstract

Background and Aims Severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) infection is a public health concern. Until 2021, more than 2 million cumulative deaths were reported worldwide. Herein, we investigated the immune profile of healthcare professionals 6 months after vaccination or exposure to SARS‐CoV‐2 in Angola. Methods This was a prospective study conducted with 1068 Angolan healthcare professionals between August and December 2021. Participants were screened for the presence of IgG and IgM against SARS‐CoV‐2. Results About 9.6% and 98.2% of the participants had prior exposure to SARS‐CoV‐2 or vaccination against it, respectively. Participants aged between 20 and 40 years (11.2%), female (12.4%), with higher educational level (12.8%), from Luanda (60.3%), and nonhealthcare professionals (8.1%) were the most affected by the SARS‐CoV‐2. Gender, education, and local residence were related to SARS‐CoV‐2 exposure ( p < 0.05). About 7.3% and 98% of the exposed population developed IgM and IgG after 3 months of exposure, respectively. The AstraZeneca vaccine was the most used, followed by the Jonhson & Johnson and Sputinik. Almost all (98%) participants vaccinated with AstraZeneca had immunity >3 months. Individuals who received only the first dose regardless of the type of vaccine had a higher immunity duration (>3 months) than those who received two doses. For individuals who received the Sputnik and Johnson, the average immunity was lower (<3 months), especially among those who were older (over 40 years old) and exposed to SARS‐CoV‐2. Conclusion We observed a high adherence rate to vaccination and a long immunity duration. The immunity duration depended on the type of vaccine. Further studies on the immunity profile in the population exposed to SARS‐CoV‐2 must be carried out in the general population from Angola to assess antibody‐waning periods.