A 3rd shot? A new booster? Vaccine makers race to trials to beat variants

Enlarge / COVID-19 vaccine at a vaccination center in Madrid on Feb. 26, 2021. (credit: Getty | NurPhoto)

With worrisome coronavirus variants seemingly emerging and spreading everywhere, lead vaccine makers are wasting no time in trying to get ahead of the growing threat.

This week, Moderna and partners Pfizer and BioNTech announced they have kicked off new vaccine clinical trials aimed at boosting the effectiveness of their authorized vaccines against new, concerning SARS-CoV-2 variants—primarily B.1.351, a variant first identified in South Africa.

In a set of studies published last week in the New England Journal of Medicine, both the Moderna mRNA vaccine and Pfizer/BioNTech mRNA vaccine spurred antibodies in vaccinated people that could neutralize the B.1.351 variant. But the levels of those neutralizing antibodies were significantly lower than what was seen against past versions of the virus. (Both vaccines performed well against the B.1.1.7 variant, first identified in the UK, which is expected to become the dominant strain in the US next month.)

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