Mix-and-match J&J Covid booster boosts immune response after Pfizer vaccine, study finds

Their small study of 65 volunteers, who initially received two doses of the Pfizer/BioEntech vaccine, showed that using the J&J Janssen vaccine as a booster resulted in a slow but effective response against the original strain of the virus, as well as delta and beta. A more sustained antibody response occurred. Variants, he said.

Their study suggested that the Pfizer/BioNTech booster produced a faster and stronger immune response that subsided rapidly.

Dr. Dan Barouch of Beth Israel Deaconess Medical Center and Harvard Medical School, who led the study team, told CNN: “Both vaccines boost antibody titers very well. At the fourth week, neutralizing antibody levels were comparable. ”

But after four weeks, antibody levels began to drop in those who received the Pfizer vaccine, while they continued to rise in those who received the J&K vaccine. The J&J vaccine also increased the number of immune cells called CD8 T cells.

CDC says all vaccinated adults should get a Covid-19 booster shot because of the Omicron version

Antibodies are the first line of immune defense that can stop the virus from ever infecting cells, while T cells come later and destroy the infected cells. This T-cell defense does not prevent mild infections, but may prevent them from progressing to severe disease.

While the study did not include the Omicron version, Barouch said the findings could be important for coming up with ways to fight the latest version.

“For variants such as Omicron that can partially evade antibody responses, CD8 T cell responses may be particularly relevant for protection,” he said. “We think they are relevant in general but they may be particularly relevant if a variant emerges that can largely evade antibodies.”

“Now we don’t know for sure about Omicron, but as I’m sure you know, there’s a lot of concern or speculation that it may result in vaccine avoidance, at least to some degree, probably enough.” There may be degrees. Induced antibodies. For a boost, you want a boost to increase both antibody and T-cell responses.”

Barouch said his team has submitted the findings to a peer-reviewed journal and in the meantime posted it online without any peer review. Preprint Server MedRxiv.