Three jabs best for preventing Covid infections, global analysis finds

The largest study of its kind found that three doses of the same Covid-19 vaccine or a combination of jabs work equally well in preventing infections.

The effectiveness of individual coronaviruses vaccines is well known, but the evidence around combinations of jabs has been less clear for certain groups.

A global analysis of data from more than 100 million people shows the number of doses is the key to boosting immunity. The findings have been published.

The study shows that three doses of the same vaccine or a combination of different types work well against Covid-19 infections.

Despite a rapid decline in Covid-19 infections and deaths, it is important to understand which vaccine combinations are most effective.

The World Health Organization Covid-19 databases were searched by the Chinese University of Hong Kong. There are 53 studies involving 100 million people.

Heterologous regimen is when you receive three doses of the same vaccine, but with a different dose than the two primary ones.

After taking into account the design and quality of the study, the researchers found that three doses of any vaccine appear to be the most effective against Covid-19 infections and the most effective in reducing hospital admissions.

The results show that immunity is higher in all age groups, even in the over-65s, if there is a three-dose regimen.

The study found that a third dose of the booster improves protection compared to two.

The effectiveness of three-dose vaccine regimen against Covid-19 related death is uncertain.

The researchers acknowledged some of the study's limitations, including that they didn't evaluate the optimum time interval for boosting.

The researchers concluded that an mRNA booster is recommended to supplement any primary vaccine course.