A third dose of the AstraZeneca coronavirus vaccine more than six months after the second dose boosts the immune system, according to a study by the University of Oxford.
Both doses of this vaccine have been shown to be extremely effective, even against the most contagious Delta mutation, but it remains unclear how much this protection diminishes over the months.
The British researchers, who developed the AstraZeneca vaccine, concluded that a third dose would actually restore the body's declining defenses if needed, by producing antibodies and so-called T-lymphocytes.
They noted, however, that while it was important to be ready to receive the booster dose for the time being, the priorities had to be different.
As Professor Sir Andrew Pollard explained, "giving third installments while other countries have no installments is not acceptable".
The study also showed that larger gaps between the first two doses, up to 45 weeks, lead to a stronger immune response against the coronavirus.
The Oxford research team has also begun a study on a modified vaccine targeting the Beta mutation, which was originally detected in South Africa.