Recent research highlights the immune advantages of breakthrough Omicron infections amid ongoing variant concerns.
Omicron subvariants continue to drive COVID-19 cases globally, with Singapore’s Ministry of Health reporting the first local cases of the BA.4 and BA.5 variants on Sunday (May 15).
Two recent studies indicate that breakthrough infections with the Omicron variant—where vaccinated individuals contract the virus—provide more effective protection than receiving a second vaccine booster. Conducted by BioNTech and the University of Washington in partnership with Vir Biotechnology, the studies analyzed immune responses across different groups based on their infection status and vaccination history, as reported by Fortune on May 16.
However, health experts caution against attempting to contract the Omicron variant intentionally, as the risk of “long COVID”—where individuals experience lingering symptoms for months—remains significant, affecting up to one-third of those infected.
In Singapore, the Ministry of Health recommends a second booster for individuals over 80 years old, residents of senior care facilities, and those with significant medical risk factors who are at higher risk of severe disease. People aged 60 to 79 are also eligible for the second booster if they wish to receive it, with the shot administered approximately five months after the first booster.
The study conducted by BioNTech found that individuals with a breakthrough Omicron infection exhibited a stronger response in their B-cells—white blood cells crucial for antibody production—compared to those who received boosters without prior infection.
Similarly, the University of Washington study analyzed blood samples from vaccinated individuals who were subsequently infected with either the Delta or Omicron variants. It compared these samples with those from individuals who were infected prior to vaccination, those who were vaccinated without ever contracting COVID, and those who were infected without vaccination. The findings revealed that vaccinated individuals who were infected with Omicron developed antibodies that provided robust protection against other variants. In contrast, unvaccinated individuals infected with Omicron did not demonstrate the same level of immune response.
The Fortune report also emphasized that immune responses, whether from infection or vaccination, tend to diminish over time.
In the United States, where a surge in COVID-19 cases is anticipated this autumn, the Centers for Disease Control and Prevention recently updated its vaccination guidelines. They advised individuals who have been infected within the past three months to consider delaying their second booster until later in the year. The guidelines suggest that a second booster may be more crucial in the fall of 2022 or if a new vaccine targeting future COVID-19 variants becomes available.
