1Life Healthcare : What To Know About The COVID-19 Delta Variant

Studies have found all three vaccines authorized for emergency use (Pfizer, Moderna, and Johnson & Johnson) to be effective against the delta variant for those who have had both doses. For instance, the PHE found that both doses of the Pfizer vaccine were 88% effective against symptomatic disease and 96% effective against hospitalization, with the delta variant. The key to the vaccines' effectiveness, though, is receiving the full dosage. According to the same study, one dose was only 33% effective against symptomatic disease.

That being said, no vaccine is 100% effective. A portion of those vaccinated with COVID-19 have been infected after vaccination - known as 'breakthrough cases'. More research is underway to understand the prevalence and significance of breakthrough cases with the delta variant, but so far, severe disease in vaccinated individuals seems to be rare.

At this point, it is not known whether a booster shot will be needed to protect against the delta variant or other COVID-19 mutations. Vaccine makers, however, are currently exploring this possibility. Pfizer has announced plans to seek emergency use authorization for a booster dose later this year.