Michael Osterholm – a leading member of the United States President’s coronavirus transition team – has said he is “convinced” by data indicating the UK COVID-19 variant is more deadly, even as United Kingdom officials downplay the limited and “uncertain” evidence.

Meanwhile, Moderna announced today that it will “test an additional booster dose of its COVID-19 Vaccine (mRNA-1273)” to see whether it can further increase neutralizing antibodies against emerging strains “beyond the existing primary vaccination series”.

Late on Friday evening, UK Prime Minister Boris Johnson announced that the SARS-CoV-2 variant, also known as B.1.1.7, “may be associated with a higher degree of mortality”: potentially by up to 30%.

But the government’s chief scientific adviser, Sir Patrick Vallance, was quick to flag that the current data available – published by Nervtag, a government advisory committee – was “not yet strong”.

The report concluded there was “a realistic possibility” that infection with B.1.1.7 “is associated with an increased risk of death”.

Vallance noted: “There’s a lot of uncertainty around these numbers and we need more work to get a precise handle on it, but it obviously is a concern that this has an increase in mortality as well as an increase in transmissibility.”

The variant, which was first detected in September 2020, was previously understood to be around 30-70% more transmissible than the Wuhan strain.

Vallance explained that around 10 in 1,000 men in their 60s infected with the Wuhan strain would be expected to die with the virus. “With the new variant,” he said, “for 1,000 people infected, roughly 13 or 14 people might be expected to die.”

Despite this, Michael Osterholm – epidemiologist and a member of President Joe Biden’s coronavirus transition team – has said he is “convinced” that B.1.1.7 is deadlier after reviewing the UK report.

Osterholm, who has also reviewed other unpublished data, said: “The data is mounting — and some of it I can’t share — that clearly supports that B.1.1.7 is causing more severe illness and increased death.”

The US Centers for Disease Control and Prevention (CDC) has begun reviewing the data, it confirmed to CNN on Saturday: “The CDC has reached out to UK officials and is reviewing their new mortality data associated with variant B.1.1.7.”

The Nervtag report collected data from three independent analyses, led by University of Exeter, Imperial College London, and London School of Hygiene & Tropical Medicine.

Moderna Latest To Claim Vaccine Effective Against Key Variants

Given this uncertainty, questions have naturally been directed toward those organizations developing COVID-19 vaccines, notably as to whether these candidates can protect against these variants.

As of Monday morning, Moderna — whose mRNA vaccine has so far been approved for emergency use in at least 10 blocs including the UK, the US and the European Union — has claimed its candidate appears to retain its efficacy against the B.1.1.7 and South Africa-identified (B.1.351) variants.

In the study, which is yet to be peer-reviewed, researchers looked at blood samples from eight participants who had previously received the recommended two doses during Phase 1 trials.

In the case of the B.1.1.7 variant, they reported the mutated virus posed no significant impact on titers: a means for measuring the amount of antibodies in a blood sample.

Tests on B.1.351 showed a “six-fold reduction in neutralizing titers” although “neutralizing titer levels with B.1.351 remain above levels that are expected to be protective”, according to the company media release. But the sample size is surprisingly low, with only eight participants and the study is based on an in-house, un-peer reviewed study,

Last week, Pfizer made a similar claim after testing only 16 blood samples: a startlingly low number given the number of participants involved in their clinical trials. Critics had said Pfizer had been overly optimistic in its interpretation of the data.

Meanwhile, Moderna is also “advancing an emerging variant booster candidate (mRNA-1273.351) against the B.1.351 variant first identified in South Africa”.

It aims to test the candidate in preclinical studies and a Phase 1 study in the US “to evaluate the immunological benefit of boosting with strain-specific spike proteins” and “expects that its mRNA-based booster vaccine will be able to further boost neutralizing titers in combination with all of the leading vaccine candidates”.

Image Credits: Moderna.