A new study found that antibody levels were boosted in people who got a shot of the AstraZeneca coronavirus vaccine and then a shot of the Pfizer vaccine, Reuters reported on Monday.

If the results hold, they could lead countries to combine the AstraZeneca vaccine with another vaccine to improve results. The AstraZeneca vaccine is in wide use in some countries, though the Pfizer and Moderna vaccines are much more widely used in the United States.

The study was conducted by the Korea Disease Control and Prevention Agency in South Korea and involved 499 medical workers.

In the study, 100 participants received one shot each of the two vaccines, while 200 others took two doses of the Pfizer shot and the remaining participants got two doses of the AstraZeneca shot.

Those who received a shot of AstraZeneca and then a shot of the Pfizer vaccine saw their neutralizing antibody levels boosted six times compared to those who got the two AstraZeneca shorts, Reuters reported.
Antibodies prevent a virus from replicating in cells. The results showed that the mixed AstraZeneca-Pfizer shots had the same effect of neutralizing antibodies for those who received the two Pfizer shots, according to Reuters.

The new study comes as British scientists conducted their own study in June, showing that an AstraZeneca shot followed by Pfizer can produce the best T-cell and antibody response to the virus.

The delta variant of the COVID-19 virus has fueled the rise of cases throughout the world, with unvaccinated people being the vast majority of those contracting the virus.