See How Vaccines Can Make the Difference in #Delta Variant’s Impact - The New York Times
▻https://www.nytimes.com/interactive/2021/08/12/science/covid-delta-breakthrough.html
Here’s how a Delta-driven outbreak might unfold in two hypothetical groups of people, all of whom are exposed to enough of the virus to infect a person:
In either scenario, the infected group is just the start. The Delta variant is the most transmissible version of the virus yet. Those infected are likely to spread the virus to others at an even higher rate than older versions of the virus would have spread.
With a higher number of people infected in the group with the low vaccination rate, many more people in their larger community are also likely to become infected with the virus, especially if the #vaccination rate is similarly low elsewhere in that community.
This is true even among people who have been infected with #Covid-19 before: Those who have previously had the virus are more than twice as likely to become reinfected by the Delta variant if they are unvaccinated.
Conversely, there is a lower risk in general of virus exposure in a highly vaccinated community. But experts say outbreaks that have occurred in heavily vaccinated groups, like the July 4 cluster in Provincetown, Mass., or those in two San Francisco hospitals, have shown the power of the vaccines: Remarkably few people faced severe illness, contrasted with how a similar outbreak may have played out in a community with a low vaccination rate.
Of at least 965 positive cases that were traced to heavily vaccinated Provincetown, where around 60,000 people had gathered for the holiday weekend, not a single death was reported and just seven people were hospitalized.
While a recent Centers for Disease Control and Prevention report suggested it’s possible that fully immunized people may also transmit the virus to others as easily, another recent study has shown that those who are fully vaccinated may carry the virus, and therefore be contagious, for fewer days than their unvaccinated counterparts. That suggests an even bigger overall difference in #transmission between places with high and low vaccination rates.