Moderna defends Covid-19 shot as questions on heart risks mount

Moderna's vaccine appears linked to increased chances of an inflammatory heart condition known as myocarditis in young men.. PHOTO: NYTIMES

NEW YORK (BLOOMBERG) - Moderna held a brief conference call to defend the safety of its Covid-19 shot from a barrage of questions about associated heart risks in young people.

Chief medical officer Paul Burton acknowledged on the Thursday (Nov 11) call that the company's vaccine does appear linked to increased chances of an inflammatory heart condition known as myocarditis in young men.

Moderna maintains that the shot's benefits continue to outweigh the extremely rare risk of myocarditis, he said.

Moderna's market value has recently taken a blow on the heart-risk concerns, along with a forecast cut and a legal battle with the government over patent rights.

Shares of the Cambridge, Massachusetts-based biotech plummeted 34 per cent this month through Wednesday's close. They fell as much as 3.2 per cent as of 12.16pm in New York.

Sweden and Denmark have halted use of Moderna's shot in younger people as they monitor the risk of heart inflammation, while Germany has favoured the vaccine from Pfizer and BioNTech over Moderna's in younger and pregnant people.

Moderna has fallen behind those main rivals in clearances for booster shots and use in children.

Meanwhile, the US Food and Drug Administration has required additional time to assess Moderna's emergency request to approve the vaccine in adolescents aged 12 to 17 as it examines the rare risk of myocarditis. The regulatory review may not be completed until January.

That's conceded the US adolescent market largely to Pfizer and BioNTech, which won clearance for those age 12 and up in May.

About 60 per cent of teens have gotten at least one shot of the Pfizer-BioNTech vaccine, according to data from the Centres for Disease Control and Prevention.

Compared with the Pfizer-BioNTech shot, Moderna's has led to only 10 additional cases of myocarditis per 100,000 inoculations among males age 12 to 29, Burton said in the conference call.

The occurrence of the side effect in males suggests that the hormone testosterone may be important, he said.

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The chief medical officer took only a handful of questions before the call concluded.

The side effect issues only add to the vaccine maker's recent woes. Moderna is in a legal tussle with the the US National Institutes of Health over who gets credit for inventions related to the company's Covid-19 vaccine.

The government is objecting to Moderna listing only company scientists, and not those from the NIH's Vaccine Research Centre, as inventors on a patent application.

The company also this month cut its vaccine production forecast for the year and lowered its projection for 2021 Covid-19 vaccine sales.

Officials cited logistical issues that indicate it is struggling to shift from its mostly domestic vaccine business in the first half of the year to delivering to international locales.

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