SEOUL (SOUTH KOREA) – A study from South Korea has showed that a mixed vaccination of first AstraZeneca and then a Pfizer COVID-19 shot boosted neutralizing antibody levels by six times compared with two AstraZeneca doses,
The study involved 499 medical workers – 100 receiving mixed doses, 200 taking two doses of the Pfizer/BioNTech shot and the remainder getting two AstraZeneca shots.
All showed neutralizing antibodies, which prevent the virus from entering cells and replicating, and the result of the mixed schedule of vaccines showed similar amounts of neutralizing antibodies found from the group that received two Pfizer shots.
A British study last month showed similar results – an AstraZeneca shot followed by Pfizer produced the best T-cell responses, and a higher antibody response than Pfizer followed by AstraZeneca.
The data provides further support for the decision of several countries to offer alternatives to AstraZeneca as a second shot after the vaccine was linked to rare blood clots.
The South Korean study also analysed neutralizing activity against major variants of concern, the Korea Disease Control and Prevention Agency (KDCA) said.
None of the groups demonstrated reduced neutralising activity against the Alpha variant, first identified in Britain, but the neutralization titre decreased by 2.5 to 6 fold against Beta, Gamma and Delta, first detected in South Africa, Brazil and India respectively.
Aspen, which has been contracted by J&J to manufacture the vaccines in South Africa in a process called ‘fill and finish’, had been sourcing APIs from the Baltimore plant and was asked to destroy 2 million doses as part of the finding of the FDA.
The supplies will also be distributed to other African countries under the African Vaccine Acquisition Task Team under which J&J has committed to supply 220 million doses of the single shot vaccine, Aspen said.
Africa’s dependence on imports of COVID-19 vaccine has left it vulnerable to repeated waves of the coronavirus, raising demands for vaccine production facilities in the continent.
It has administered just 60 million vaccine doses in a population of 1.3 billion due to restrictions on shipments from vaccine producing nations.
South Africa’s Biovac Institute struck a deal with Pfizer last week for a “fill and finish” arrangement to produce 100 million vaccines by 2022-23.
“Supply for Africa and South Africa is particularly rewarding, given the current global inequality in accessing vaccines,” Stephen Saad, chief executive of Aspen said in a statement. “This represents a big step forward in ensuring that Africa can address its healthcare priorities.”
