So who’s getting COVID-19 these days?

Data and Metrics Infection and Spread Vaccines

A: Unvaccinated people, for the most part.

Q: Will the “delta” variant change that?

A: Not likely.

As new cases of COVID-19 continue to decline in the US 🇺🇸and Canada 🇨🇦, but are rising steeply elsewhere (UK 🇬🇧and South Africa🇿🇦, we see you 🤗💕!), you might be wondering who is bearing the burden of new cases.

The answer is pretty straightforward: Most new COVID-19 cases in most settings are among people who aren’t fully vaccinated.

🧮A concrete example might help here: In King County, Washington (a large county of 2.3 million people including Seattle), epidemiologists analyzed 15,397 cases of COVID-19 from April and May 2021 (see linked story here).

📈During that time period, King County crossed the 50% vaccination mark. If vaccines didn’t protect people from COVID-19 at all, we might expect to see the cases split about 50/50 between vaccinated and unvaccinated people.

😮But that’s not what happened. Of the new cases in King County in March and April, 14,895 — 96.7% — were among people who were not fully vaccinated at the time of their diagnosis. Similar results were found for Washington State as a whole, and in Oregon.

📰We can also see a similar trend at the population level: A Washington Post analysis (linked below) looked at the relationship between county-level vaccination coverage and COVID-19 rates. The relationship was strong: High vaccination rate counties had low and declining numbers of cases. Counties with low vaccination coverage had high and increasing case rates.

🦠This same effect can be seen in the UK, which has among the highest vaccination coverage rates in world as well as steeply rising COVID-19 cases, likely due to the very infectious delta variant of the virus. In an analysis of 33,206 delta variant COVID-19 cases in England (part of the UK) from early February through early June 2021, only 1,785 — 5.3% — were among the fully vaccinated. (See super nerdy 🤓tweet thread about this analysis from James Ward linked below!)

💉💉While we hate to see cases climbing in the UK, this analysis confirms the effectiveness of available vaccines against the delta variant, and confirms the added protection from complete (two-dose) vaccination over just one dose.

🧑🏿‍🤝‍🧑🏽Bottom line: Vaccination offers excellent individual protection against COVID-19, and high vaccination coverage in the population is our best route to driving down transmission and ending the pandemic.


Washington Post story

James Ward tweet thread on England’s cases and the delta variant

Link to Original FB Post