The US biotech said that data from a just completed clinical trial not yet peer reviewed showed the revamped vaccine was able to deal with nine mutations found in the beta variant as well as the alpha strain of the virus that first emerged in China in late 2019, kicking off a worldwide panic.

According to Moderna, four of the mutations targeted by the updated vaccine are shared with omicron, the variant now in widest circulation.  A 50-microgram dose (the same strength as the original) doubled the antibodies against omicron six months after injection compared with the original booster at the same dosage. 

The updated shot also increased antibody levels against the delta variant six months after injection, though they were lower than the response observed with omicron and did not show superior results in comparison to the original booster, the biotech said. The most common side effects were injection site and muscle pain, fatigue and headache.

In the trials, 895 participants received a single booster dose of the newest version containing either 50 or 100 micrograms. The average age of the cohort was about 50 years, and 56% were female. Most of the trial population was white, while 13% were Hispanic and 6% Black in the group that received the 50-microgram dose.

Moderna is developing an additional Covid vaccine that includes the Wuhan strain and 32 mutations present in the omicron variant. According to CEO Stephane Bancel, this is the company’s lead candidate for a booster to be given in the US and Europe this autumn. Initial data is expect during the current second quarter.

BioNTech and Pfizer are also developing new shots targeting multiple virus variants. The German and American partners have said they plan to present trial data during April. The target of all the newly developed vaccines is to come to terms with the evolution of the spike protein during mutation, which reduces the efficacy of the shots.

The vaccine makers continue to maintain that two doses of their current versions still provide strong protection against hospitalization and that three shots boost protection against both infection and hospitalization.

Worldwide, the discussion continues as to whether a fourth booster should be recommended for vulnerable populations, including the elderly (though there seems to be no consensus as to whether this should be given to people aged 50, 60, 70 or even 80) as well as the immunocompromised.

Author: Dede Williams, Freelance Journalist