By Dr Tom Frieden, Covid19 Response New York.
I’m hearing from vaccinated people who are frightened about breakthrough cases, the Delta variant, and new waves of Covid. But it’s not vaccinated people who should be most concerned. Here’s what I expect to happen over the coming weeks.
Globally, we’re far from the end of the pandemic. Delta is at least two times more contagious than the original virus, which means it will infect and kill more people.
Many countries have so far avoided big surges but haven’t had access to the vaccines needed to vaccinate their populations. Many of these countries will likely see explosive spread of Covid over the coming weeks and months.
But in many places with high rates of vaccination, including much of the US, the worst is over. Though we’ll likely see big increases in US cases, future waves won’t be as deadly. That’s because 80% of the most vulnerable Americans—people over 65—are fully vaccinated.
Fewer vulnerable people means fewer deaths. Whereas the infection fatality rate in the US before vaccines was 1 in 200, it could be less than 1 in 500, or as low as 1 in 1,000, in the coming months because of vaccine protection—even if we see many breakthrough infections. If disease continues to spread, deaths may increase, particularly among adults who are not vaccinated. Because the most vulnerable are vaccinated, the overall increase will be much smaller than past horrific increases.
In the months ahead, more cases won’t correlate to more deaths in the same way as earlier in the pandemic. This graph from the UK shows why. Age matters—a lot. Vaccines will save tens of thousands of lives but are not 100%. They provide great protection, not perfect protection. More cases → more breakthrough infections. Breakthrough infections are expected, but vaccines drastically reduce risk of hospitalization & death from Covid.
When infections do occur among vaccinated people, the vast majority of these cases are mild. For most, Covid is no more serious than the common cold. They’re also less likely to spread the virus, so people around them are safer, although not completely protected. Unfortunately, some breakthrough infections will be less mild, requiring hospitalization and, in rare cases, resulting in death. That doesn’t change the reality that vaccination is the best way to protect ourselves from Covid.
We need better data on severe breakthrough infections, but my guess is that they’re more likely to occur in people of advanced age or with serious underlying conditions. It’s possible that the mRNA vaccines are more protective than other vaccines. Sometimes it can be hard to determine whether Covid was the true cause of death in patients receiving palliative care or already very ill, which complicates our understanding of the impact of breakthrough infections in certain groups.
It’s neither necessary nor wise for our public health systems to try to track every single mild breakthrough case. Instead, we should focus on investigating all infections as part of specific population-based studies, and also track all severe Covid illness after vaccination.
When you see headlines claiming a significant proportion of hospitalized patients somewhere are fully vaccinated, don’t be alarmed. Most of those stories actually underscore that vaccines are working exceptionally well against variants—including Delta.
The worst is over in the US, but, on average, 200-300 people are still dying every day from a disease that didn’t exist 18 months ago. If that rate continues for the next 12 months, that would be 100,000 deaths—more, even, than from the horrific opiate epidemic.
Delta is spreading. How the virus affects you when you encounter it depends on whether your body has been prepared by the vaccine to recognize and fight it—or is caught off guard. Unvaccinated people should be concerned about the rapid rise of Delta, which now makes up at least 83% of sequenced cases in the US.
The more uncontrolled spread, the more risk of even more dangerous variants. Vaccination, masks, ventilation and distancing can stop Covid, including Delta. Variants remain the wild card for the trajectory of the pandemic. Delta may not be the worst strain the virus deals us. We can reduce the risk of other dangerous variants by vaccinating widely and also tamping down spread.
You can follow @DrTomFrieden.
