Booster vaccine combination raises antibodies: study

The combination of vaccines against COVID produces as many or more antibodies as the use of it vaccine as reinforcement, according to preliminary results of a highly anticipated trial sponsored by the Government of USA.

The trial is the first major US study comparing the effects of using different vaccines as a booster or initial vaccines. The complex nine-arm trial involved more than 450 people and measured the effects of administering a booster vaccine from Moderna Inc., Pfizer Inc.-BioNTech SE, or Johnson and Johnson to those who had originally received a different vaccine.

Overall, the results showed that the combination resulted in comparable or higher levels of neutralizing antibodies compared to boosting with the same vaccine, the researchers said in a preliminary version of the study published on medRxiv.org. The adversity rates were similar in all the different booster groups, the study found.

“These data suggest that if a booster vaccine is approved or licensed, it will generate an immune response independent of the primary vaccination regimen against COVID-19,” the researchers concluded.

The results of the ongoing trial have not yet been peer-reviewed or published in a medical journal. More details about the study are expected to be revealed Friday afternoon at a meeting of the advisory panel of the FDA, where the investigators conducting the trial will give a presentation on their initial findings.

Mixing and matching reinforcements has become an increasingly important topic. Many countries outside the US have used the method in an attempt to maximize the effectiveness of the vaccine or avoid unusual side effects associated with some vaccines.

In the US, some people who received the Johnson & Johnson vaccine may be interested in receiving a messenger RNA vaccine as a booster. Additionally, combining could make it easier to implement boosters more broadly, as people receiving boosters could receive any COVID vaccine available at their pharmacy and would not have to search for the specific vaccine they had previously received.

Outside of the US, concern over isolated instances of blood clots associated with the AstraZeneca Plc vaccine led many countries in Europe to discontinue use of the vaccine and instead administer a second, different dose. In the UK, health authorities implemented a booster program for an additional dose of Pfizer vaccine as the preferred option, and also offered half a dose of Moderna vaccine as an alternative.