Mix and match J&J Covid booster raised immune response after Pfizer vaccine

J&J vaccine as a booster for people initially immunized with the Pfizer/BioNTech vaccine produces a strong immune response and may do more to elicit protection against severe disease, researchers reported Sunday.Their small study of 65 volunteers who all initially got two doses of Pfizer/BioNTech’s vaccine showed that using the J&J vaccine. They also said that a booster produced a slower but more sustained antibody response against the original strain of the virus, as well as the Delta and Beta variants.

The Pfizer/BioNTech booster produced a quicker and stronger immune response that dropped off faster. Dr. Dan Barouch of Beth Israel Deaconess Medical Center and Harvard Medical School, who led the study team, said that both vaccines boost antibody titers very well. At week four, neutralizing antibody levels were comparable.

Antibody levels after four weeks began to drop off in people who got boosted with the Pfizer vaccine while they continued to increase in people who got J&J vaccine. J&J vaccine also increased the numbers of immune cells called CD8 T cells. Antibodies are the first line of resistant protection that can stop a virus from ever infecting cells, while T cells come in later and destroy infected cells.

This T-cell defense prevents mild infections but can stop them from progressing to severe diseases. While the study did not include the Omicron variant, Barouch said the findings might be necessary for coming up with ways to fight the latest variant.