mRNA vaccine doses from the US manufacturer Moderna (archive image)
Photo: DADO RUVIC / REUTERS
According to initial data from the US company, a booster dose of Moderna's corona vaccine works well against coronavirus variants.
On Wednesday, the company published the first interim results from an ongoing Phase II study of two different so-called booster doses that are administered after full immunization.
On the one hand, the company is testing the effectiveness of a booster vaccine for its mRNA-1273 vaccine, which has already been approved in many countries around the world.
In addition, Moderna has developed another booster dose based on the virus variant B.1.351, which was first discovered in South Africa: mRNA-1273.351.
Both would have caused the development of antibodies against this virus variant and the virus variant P1, which was first discovered in Brazil - the newly developed booster variant with regard to B.1.351 even more clearly.
In addition, both booster vaccinations were well tolerated.
The company plans to publish a preprint for the study soon.
"Our mRNA platform enables the rapid development of vaccine candidates for important virus variants," says Stéphane Bancel, Chief Executive Officer at Moderna, according to a press release.
"In this way, we may be able to adapt vaccines to new variants more quickly in the future."
In the ongoing phase II study on booster vaccinations, three different booster strategies are being tested on 40 participants.
One group was vaccinated with the vaccine developed on the basis of the variant discovered in South Africa (mRNA-1273.351).
A second received a booster vaccination with the original vaccine already used for the first two doses (mRNA-1273).
The third group received a booster vaccination consisting of 50 percent each of mRNA-1273.351 and mRNA-1273.
In the study, the antibody titers, i.e. the amount of antibodies in the test subjects after the first series of vaccinations, were tested first.
The researchers observed that 37 of the 40 participants six to eight months after the second vaccination dose still had sufficient neutralizing antibodies against the wild type of Sars-CoV-2.
However, the titers against variants B.1.351 and P1 were very much lower.
Two weeks after the booster vaccination, the antibody titers both against the wild type and against the two variants rose sharply in all participants.
Above all, the newly developed booster vaccination mRNA-1273.351 seems to produce a good immune response.
In the study, the usual vaccine side effects occurred, headache, pain at the injection site or fatigue.
Several pharmaceutical companies are currently researching vaccines that are also effective against the newly emerging corona variants.
B.1.351 is of particular concern because, according to all previous findings, the vaccines that have already been approved seem to be less effective against the variant discovered in South Africa.
Clinical studies run in three phases, in which a vaccine is first tested for efficacy and safety on a smaller number of subjects.
In the final phase, the number of participants will then be expanded to tens of thousands.
Only when a vaccine candidate has successfully passed all three phases can the manufacturer apply to the drug authorities for approval.
However, since the previously approved corona vaccines can be quickly adapted to any variants that occur, the EU Commission wants to regulate by law that a new approval is not required for every adaptation.
kry / dpa