The CDC’s Delta Variant Panic

The agency spreads needless worry about vaccinations

WSJ editorial.

"As the coronavirus evolves, so does the science. The Delta variant is creating uncertainty about how much vaccines prevent transmission, but the overwhelming evidence shows they are highly protective against severe illness. Please get vaccinated if you aren’t already.

That should have been the Centers for Disease Control and Prevention’s straightforward message to Americans this week, along with a candid analysis of its evidence.

Instead, the CDC on Tuesday issued murky new guidance, without backup evidence, recommending that vaccinated people resume wearing masks indoors in some cases because unpublished studies suggest they could transmit the virus. But on Thursday the Washington Post ran an alarmist story on an internal CDC slide presentation with the unpublished evidence, which triggered a media panic that could undermine vaccinations. Only on Friday afternoon did the agency release some of its evidence and offer a calmer explanation.

What a fiasco. The CDC should be a source of fact and reason, not a hair-on-fire spreader of fear. The agency could start by explaining that Covid cases have been increasing across the U.S. and that more vaccinated individuals are testing positive. But most of these “breakthrough” cases are mild or asymptomatic.  

Now, let’s go to the slide deck, please. The CDC estimates there are about 35,000 symptomatic infections among 162 million vaccinated Americans a week. As cases have increased nationwide, so have breakthrough infections. This is to be expected. But recent studies show that vaccines are still 88% protective against symptomatic illness and 96% against hospitalization and death.

Next slide. Vaccinated people are making up a larger share of the hospitalized population and deaths than in the winter. That’s because most older people who are at higher risk have been vaccinated, and vaccines aren’t 100% effective. This doesn’t mean that vaccines don’t prevent severe illness, and the vast majority of people who are hospitalized are unvaccinated.

Real-world evidence from hospitals indicates that vaccines are only about 87% preventive against hospitalizations. That’s lower than published studies, but this may be because vaccines are less protective for some groups. For instance, vaccines are only about 59% protective against Covid hospitalization among the immuno-compromised and only 85% against severe illness among nursing home residents.

An important footnote: Vaccines are more protective in nursing homes where a larger share of the population are vaccinated. That’s why it’s so important for nursing-home workers to be vaccinated even if they themselves are at low risk.

Which brings us to the Delta variant. CDC evidence suggests Delta is more than twice as transmissible as the original virus strain, akin to the chickenpox, which is why cases are rising even in places with relatively high vaccination rates. But don’t freak out like the CDC. Vaccines are still very protective.

Evidence indicates the Delta variant replicates much faster and produces higher viral loads in respiratory passages that allow it to spread more. There’s also some evidence that people infected with Delta are contagious for longer. It’s still uncertain whether breakthrough Delta cases can transmit the virus as much as unvaccinated individuals do.

A study of a July outbreak from Provincetown, Mass., found that infected vaccinated and unvaccinated individuals had similar viral loads, indicating that both groups are equally likely to spread the virus. But vaccinated individuals are still less likely to spread the virus because they are less likely to become infected.

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Now the CDC is recommending masks again based on evidence of the Delta’s increased transmissibility and vaccination rates that are leaving most places short of herd immunity. The risk is that some people may conclude from this new CDC guidance that, since we still need masks, there’s no need to be vaccinated. That is not true. Masks can help modestly limit the spread while we try to increase vaccination rates. The more people who get vaccinated, the less the virus will spread.

But let’s be clear, unlike the CDC: The virus will never be eradicated. It will eventually become endemic, and the public-health goal is to protect people from getting severely ill.

Congress created the CDC precisely to address an event like Covid-19. It has some 10,700 employees. Yet time and again in this pandemic the CDC has been a source of confusion or ineptitude. And Washington wonders why Americans have lost confidence in Covid experts."