Why are we seeing more vaccinated people becoming infected with the Delta variant?

[elleng]

How protective are the vaccines at this point?
(from Calvert County, MD)

'Both of those questions have been on a lot of people’s minds since the Delta variant took hold and more breakthrough cases began to appear. Almost all COVID cases in Maryland are now caused by Delta. This variant multiplies much more quickly and at higher concentrations in the respiratory tract than previous COVID strains. Previous strains usually took 5-6 days from the time of exposure until people began to feel sick. It’s more common for symptoms from Delta to begin 3-4 days after exposure to an infected person. Studies have detected 1,000 times more virus in the nose and upper respiratory tract in early Delta infections than with previous strains of COVID.

Our Health Department epidemiologists have reviewed all COVID cases during the past 2 weeks (the time at which Delta began to dominate) to determine the likelihood of infection in vaccinated compared to unvaccinated people. It is important to keep in mind that not everyone who becomes ill gets tested. If there are significant differences in testing rates between those who have and haven’t been vaccinated, it will impact the numbers that we are able to provide as well as statewide and national statistics.'>>>

https://www.calvertcountycovid19.com/post/why-are-we-seeing-more-vaccinated-people-becoming-infected-with-the-delta-variant?

https://www.democraticunderground.com/10564862

[Fiendish Thingy]

1. False premise: we aren't seeing more vaccinated people get infected with COVID

The rate of breakthrough infections in vaccinated people remains incredibly low per capita.

The more folks who get vaccinated will necessarily increase the number of breakthrough infections, but the per capita rate will remain low.

[elleng]

2. The PREMISE:

'Why are we seeing more vaccinated people becoming infected with the Delta variant?'

[Fiendish Thingy]

3. The article you linked to is a well written, science based explainer...

But the headline is misleading.

The actual premise/headline should be “Why is the delta variant causing more breakthrough infections in vaccinated people now, than the alpha variant did back at the beginning of the year?”

[Eko]

4. Because people arent wearing masks.

And aren't getting vaccinated. So it spreads more and has more chance to mutate into something that the original vaccines aren't as good at blocking. Each time this happens the chance that it will mutate into worse strains gets higher and higher. Will that happen? Delta is a good example that is has happened and there is a new strain that might be worse. Will it keep happening? Probably but it could just die out. I could also win the lottery today.

[NNadir]

5. It is important to define what "more" means.

2% is more than 1%, but on the other hand, is not really dire.

[elleng]

6. 'Looking at close to 200 infections during the late July into early August,

unvaccinated Calvert residents are 5.3-times more likely to get infected than vaccinated residents. Another way to express this is that vaccination is 81.2% protective against infection. Over these past 2 weeks, 6 Calvert residents have been hospitalized. All were unvaccinated. During that time period, fortunately, we have not had any deaths. National data shows 88% effectiveness of mRNA vaccines against COVID infection and a clear and dramatic reduction in hospitalizations (97-98% lower risk) and death. Studies from England indicate 80% effectiveness in preventing infection and 97-98% reduction in hospitalization, so our current local data is consistent with the expected results from U.S. and U.K. numbers.'