COVID-19: Moderna or Novavax after AstraZeneca jab confers high immunity, study claims

The latest research demonstrated that the combination of a first dose of the AstraZeneca COVID-19 vaccine with the second dose of either the Moderna or Novavax vaccines produces much greater levels of neutralising antibodies and T-cells than giving two shots of the AstraZeneca vaccine. The Com-Cov research, conducted by the University of Oxford, sought to determine if combining and matching Covid-19 vaccinations throughout primary immunisation regimens have harmed or benefited the overall immunological response to vaccination, as per The Guardian. 

This discovery might be critical for guaranteeing the quick deployment of these vaccines in low and middle-income nations, where vaccine supplies have been uneven. Further, it would benefit low-income nations that have not yet finished their main immunisation campaigns since it does not require access to mRNA vaccines.  

A dosage of the AstraZeneca vaccine, accompanied by a dose of the Novavax vaccine, produced the greatest T-cell response of all. The research also suggests that giving the Moderna vaccine as a COVID booster dose to those who have already had the AstraZeneca vaccine as the first dose will lead to higher levels of neutralising antibodies and T-cells.  

“What we’re seeing is that there’s a great amount of flexibility in the primary immunisation schedule. Just because you’ve received dose one of a particular vaccine, doesn’t mean you have to receive the same vaccine for dose two,” citing Professor Matthew Snape at the University of Oxford, who led the research, The Guardian reported.   

Findings of the research

As per the research, an initial dose of the AstraZeneca or Pfizer vaccination was given to the 1,070 British volunteers, who then received a second dose of the same vaccine, or either the Moderna or Novavax jab, nine weeks later. During the analysis, it has been observed that when compared to those who got two shots of the AstraZeneca vaccination, neutralising antibody levels were seen 17 times higher among those who obtained the AstraZeneca vaccine accompanied by the Moderna vaccine, while it is four times higher in those who got the AstraZeneca vaccine with the Novavax vaccine as the second dose.  

Further, acquiring a second dose of the Moderna vaccines shot after getting the initial dose of Pfizer, resulted in 1.3 times as many neutralising antibodies as taking two shots of Pfizer, whereas receiving Novavax as the second jab produced 20% fewer antibodies. Differences in T-cell responses following combinations of various kinds of vaccinations were also observed in the study, which has been published in The Lancet journal. 

In addition, when two shots of the AstraZeneca or Pfizer vaccines produced equivalent numbers of T-cells, combining the AstraZeneca vaccination with a second dose of Moderna produced 3.5 times higher T-cells. The second dosage of Novavax increased 4.8 times the number of T-cells. Further, when the second dosage of Moderna was combined with the Pfizer vaccine, it resulted in 1.5 times more T-cells, but when the second dose of Novavax was combined with Pfizer, it resulted in fewer T-cells. According to the research, the influence of these various vaccination combinations on the Delta and Beta variants was also investigated. There was a decrease in neutralising antibodies in all instances but very little change in T-cell responses.  

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