In case you haven’t heard, there’s now a new set of vaccine booster shots that protect against the latest variant of Covid-19, BA.5. This new variant is highly infectious, and the original vaccine doesn’t protect people against it as well as it protected against earlier variants.
Now, before someone takes that last sentence out of context, let me emphasize that the original Covid-19 vaccines are still highly effective at preventing severe disease and hospitalization. Anyone who isn’t vaccinated would be well-advised to get one of those, if that’s their only option.
But the new vaccines protect against two different strains of Covid-19: the original strand and the latest Omicron variant, BA.5.
Many people are well aware that we have a new influenza vaccine every year–but what they might not know is that each year’s vaccine contains a different strain of the flu virus from the previous year. (Actually, it has up to four different strains, and any or all of them could be new.)
And yet we don’t run large, months-long clinical trials of the flu vaccine each year to measure it’s efficacy. Why not? Well, the basic designs of the flu vaccines (there’s more than one) have been tested in large clinical trials, and we know they’re safe.
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This is exactly what scientists have done with the new Covid-19 booster shots from Pfizer/BioNTech and Moderna: they simply added a new strain, in this case to match the latest Omicron variant.
