Single dose vaccine may be enough for Covid-19 survivors
CAPE TOWN - A single dose of the Pfizer and Moderna vaccine may be enough for people who have had Covid-19, two new studies suggest.
South Africa’s health ministry says it has secured 20 million doses from Pfizer, with deliveries starting in the second quarter. It also expects to receive 117 000 Pfizer shots in the first quarter from the Covax facility co-led by the World Health Organization.
The research suggests that a single dose from either vaccine is enough to turbocharge Covid-19 survivors' antibodies and destroy the coronavirus including in the more infectious 501Y.V2 variant found in South Africa.
The studies found that when people with some natural immunity are vaccinated, their blood samples show a 1,000-fold increase in neutralizing antibody titers compared to the blood samples of other vaccine recipients.
In the one study, most people had been infected with the coronavirus eight or nine months earlier, but saw their antibodies increase by a hundredfold to a thousandfold when given the first dose of a vaccine. After the second dose, however, the antibody levels did not increase any further.
Lead author of that study Dr. Mark J. Mulligan said "It's a real testament to the strength of the immunologic memory that they get a single dose and have a huge increase.”
The study, published on medRxiv, analyzed the blood samples of 32 vaccines recipients who had received both doses of the vaccine
Meanwhile, France on Friday recommended that people who have already recovered from Covid-19 receive a single vaccine dose, becoming the first country to issue such advice.
All three Covid-19 vaccines approved for use in the European Union are administered in the form of two doses, delivered several weeks apart.
The Israel health ministry has also recommended that people who have recovered from COVID-19 receive a single vaccine dose, instead of the two shots administered to those not previously infected.