One of the biggest questions surrounding COVID-19 vaccines from the likes of Pfizer/BioNTech, Moderna, Johnson & Johnson, and AstraZeneca is whether or not, and to what extent, they can prevent actual transmission of the coronavirus rather than just making someone less sick if they do contract it (the latter an important goal itself). We’re beginning to get more answers to that crucial query—and the early findings are promising.
There was already preliminary evidence in early February that the AstraZeneca vaccine, created in conjunction with the University of Oxford, cut transmission rates for the virus by about two-thirds with just a single dose.
That data will soon be confirmed, reports the Telegraph, citing sources from Public Health England (PHE), not just for the AstraZeneca vaccine but for a single dose of the two-dose Pfizer vaccine as well. And that protection against transmission appears consistent across all age groups.
This adds to evidence from two Israeli studies published this week, finding that Pfizer’s COVID vaccine significantly reduces the virus’s transmission. The joint analysis between Pfizer and Israel’s health ministry found that a two-dose regimen of the shot reduced infections by 89.4% overall (including asymptomatic cases) and 93.7% in symptomatic cases. Results were tracked via testing for COVID infections, fueled by a national COVID-tracking database in Israel. The study has yet to be peer-reviewed.
The second study examined more than 7,000 hospital staff and found about a 75% reduction in infections with Pfizer’s vaccine.
To be clear, it’s important to get vaccinated when your turn comes, regardless of how effective a vaccine is against preventing infection, as public health officials have made clear.
Given the high efficacy rates of the Pfizer, Moderna, J&J, and AstraZeneca vaccines, getting some kind of shot would still weaken the virus and at the very least lower the chances of spreading it to others.
We already know that these vaccines significantly reduce the risk of COVID-related hospitalization and deaths for those who may go on to contract it. But the ideal would be to achieve a significant level of “sterilizing immunity,” the kind that can stop widespread community spread of the coronavirus. And the information rolling in suggests this class of vaccines may meet that challenge.