'Cell' Improves COVID-19 Protection, Needs Boosted Vaccines

In late November, South African health officials reported that a previously unknown variant of SARS-CoV-2 was spreading rapidly across the country

Dr.

To find out, Balazs teamed up with a team that included Wilfredo F.

The first step is to build a harmless version of the "pseudovirus" that can be used in laboratories to evaluate the effectiveness of the three COVID-19 vaccines

The three COVID-19 vaccines include two doses of Pfizer and Moderna injections and one dose of Johnson & Johnson's vaccine

Next, Garcia-Beltran and colleagues at MGH, including hematology-oncology researcher Vivek Naranbhai, MD, obtained blood samples from 239 people who had been fully vaccinated against one of three COVID-19 vaccines

"It was important for us to have a diverse population representation in the study," Garcia-Beltran said

Blood samples were used to measure the effectiveness of each vaccine in inducing protective immunity in the form of antibodies against omega-pseudovirus, delta virus and wild-type virus, and the results were striking

"When we used samples from people who had recently received two doses of the mRNA vaccine or one dose of the J&J vaccine, we found very little neutralization of the Omicron variant pseudovirus," Balazs said

It's unclear why the messenger RNA booster significantly improved immune protection against Omicron, but one possibility, Garcia-Beltran said, is that the additional doses produced antibodies that bind more tightly to the spike protein, increasing their potency

Balazs noted that the three-dose mRNA vaccine regimen—that is, the traditional two-dose and a booster of the Pfizer or Moderna vaccines—had slightly lower levels of neutralizing antibodies to Omicron than to the COVID-19 wild-type strain or the Delta variant antibody levels

Wilfredo F.