A new study from South Korea has found that a mixed dosage of Covid-19 vaccination was able to boost the neutralizing antibody levels by six times compared to two doses of the same vaccine. The study was conducted using the vaccines from AstraZeneca and Pfizer and found that using the first dose of AstraZeneca vaccine followed by the second dose of the Pfizer vaccine boosted efficiency compared to double doses of the AstraZeneca vaccine only.
499 medical workers participated in the study. 100 of the participants were administered the mixed doses, 200 were given two doses of the Pfizer/BioNTech vaccine with the rest 99 were administered two shots of the AstraZeneca vaccine.
All of the vaccines doses generated neutralizing antibodies that prevent the coronavirus from entering human cells and replicating. The study found that the mixed schedule of vaccines showed similar amounts of neutralizing antibodies found from the group that received two Pfizer shots.
Similar results were also achieved by a British study last month in which scientists used one AstraZeneca shot followed by Pfizer dose. The researcher of the study claimed that this combination produced the best T-cell responses as well as a higher antibody response compared to a single dose of Pfizer followed by the second dose of AstraZeneca.
The latest study adds on to the body of evidence that is being sought by a number of countries to start offering alternatives to AstraZeneca as a second following the vaccine being linked to rare incidents of blood clots.
The Korea Disease Control and Prevention Agency (KDCA) said that neutralizing activity against major variants of concern was also analysed in the South Korean study.
Study results showed that reduced neutralising activity against the Alpha variant was not exhibited by any of the three groups of volunteers. The Alpha variant was first identified in Britain. However there was a reduction of between 2.5 to 6 times in the neutralization titre decreased against Beta, Gamma and the Delta variants that were first detected in South Africa, Brazil and India respectively.
(Adapted from Reuters.com)