The first “tweaked” vaccine against the worrying coronavirus variants that emerged in South Africa and Brazil has successfully neutralised them in laboratory trials, the US company Moderna has said.
The results of the small trial suggest that boosters against the variants will be feasible and could be rolled out this year to counter the threat from variants that have appeared around the world and are feared in some cases to be more transmissible or partially vaccine-resistant.
Leading companies have been racing to produce adapted versions of their Covid vaccines. Pfizer/BioNTech, which has a similar mRNA vaccine to Moderna’s, and Oxford/AstraZeneca are also in the process of developing tweaked vaccines against the South African variant, B1351, and the Brazilian variant, P1, which appear to be the major threat to current immunisation programmes.
Moderna became the first to announce results on Wednesday night. They appear to be very positive, although only basic information from an initial analysis of results is available so far.
The US company has tested both a booster shot of its standard Covid vaccine and also a tweaked version of the vaccine in people who have previously had the full double dose. Twenty adults were recruited for each arm of the trial, or 40 in total.
Two weeks after the new jab, Moderna says both the booster shot and the tweaked vaccine increased the antibodies in the blood that can neutralise the two variants of concern.
But the tweaked vaccine – called mRNA-1273.351 and designed specifically to combat the South African and Brazilian variants, which have similar mutations to the spike protein – produced higher levels of neutralising antibodies than the standard booster shot, mRNA-1273.
