As the graphs below show, Sweden’s death rate peaked in January this year, at a rate of ~ 140 per day. At that time, no one was fully vaccinated. Now the fully vaccinated rate in Sweden is over 50% and the number of deaths has dramatically declined.
But while Sweden has only recently vaccinated more than 50% of its population, Israel reached that point over 6 months ago. This difference is significant.
In the United States, the CDC has been analyzing data from a number of cohorts, both in the US and around the world, to understand how long protection from the initial COVID-19 vaccines will last. One of these study cohorts includes more than 10 million New Yorkers of all ages.
The Director of the CDC says that, through the end of July and early August this year, three points are now very clear.
Vaccine-induced protection against SARS-CoV-2 infection begins to decrease over time.
Vaccine effectiveness is generally decreased against the delta variant.
Vaccine effectiveness against severe disease, hospitalization and death remains relatively high.
Israel is now showing reduced protection against COVID infection, especially the Delta variant. The majority of the currently hospitalized patients who are fully vaccinated were vaccinated early on, are over the age of 60 and also suffer from chronic illnesses known to exacerbate coronavirus infection. The vaccine won’t have triggered an immune response in some of these patients as they had no antibodies, either because of the illness itself or because of treatment with immunosuppressive drugs. Notably, Israel is reporting almost no young vaccinated people in severe condition; in contrast, many unvaccinated COVID patients are young and healthy and their condition deteriorates rapidly.
That the effectiveness of the COVID vaccine seems to be waning over time isn’t surprising. Flu vaccines typically provide protection from infection for about 6 months.
Unfortunately, like with the flu, it’s likely we’ll be looking at booster shots.
