Immune response of mix-and-match boosters

Editor's Note

This study led by researchers at Beth Israel Deaconess Medical Center, Boston, finds that being boosted with either the Janssen (Johnson & Johnson) or Pfizer-BioNTech vaccine was associated with increased humoral and cellular immune responses. Boosting with the Janssen vaccine also was associated with durable antibody and T-cell responses for at least 4 months.

A total of 68 individuals were vaccinated at least 6 months previously with two immunizations of the Pfizer vaccine and then boosted with either the Pfizer or Janssen vaccine.

Both vaccines were associated with increased humoral and cellular immune responses, including against the Omicron variants.

The Pfizer booster was associated with a rapid increase of Omicron neutralizing antibodies that peaked at week 2 and declined by 6.9-fold by week 16.

The Janssen booster was associated increased Omicron neutralizing antibodies that peaked at week 4 and declined by 2.1-fold by week 16.

The data suggest potential immunologic benefits of mix-and-match COVID-19 vaccine regimens, the researchers say. Future studies could examine reduced booster doses and Omicron containing boosters.