Mask-Wearing and Vaccine Hesitancy Threaten Herd Immunity

As summer approaches, cases of COVID-19 will decline, but a decrease in people donning masks coupled with an increase in vaccine hesitancy could lead to a surge in cases during the winter, according to experts.

Experts from the Infectious Diseases Society of America are warning that although cases of COVID-19 will decline this summer, vaccine hesitancy and a lack of mask-wearing could spark another surge of the virus this winter.

If there is 95 percent adherence to mask-wearing this fall and winter, the United States will likely experience a “very mild” rise in COVID-19 cases and mortality, said Dr. Amesh Adalja, senior scholar at John Hopkins University Center for Health Safety, in a media call.

The country is also facing an increase in vaccine hesitancy, partly because many of those who are eligible and willing to get the vaccine have done so, and also because of the pause in the Johnson & Johnson vaccinations because of a half-dozen cases of blood clots in women.

Projections are that cases of COVID-19 and mortality will decline until the winter, but the projections include a total of nearly 619,000 U.S. deaths by August.

“We are projecting that cases and mortality will decline in the United States all the way to next winter, aided by seasonality and vaccination,” Adalja said. “What’s working against us is mobility [people moving about] and mask-wearing.”

He said there has been an increased hesitancy in the United States to get vaccinated and that’s a concern as well. “We’re seeing a slight drop in the United States after AstraZeneca halted its testing and J&J paused its vaccinations. We believe we’re going to reach a time soon where we’ll have more vaccine than demand here in the United States and that’s a big concern.”

But Adalja said in all scenarios, the best predictor of infection is mask-wearing, and the concern there is that this summer as infections decline and the virus wanes a bit because of its seasonality, people will get complacent about wearing masks.

Dr. Ali Mokdad, chief strategy officer for Population Health at the University of Washington, stressed the importance of continuing to get people vaccinated. He noted the fact that hospitals are no longer filled to capacity with COVID-19 patients as evidence that the vaccines are effective and safe.

“The biggest thing that needs to be emphasized is that the vaccines are something that will change your life,” Mokdad said. “That messaging has been missing. The people haven’t thought of this vaccine as something that improves their lives personally.”

He said the few cases of re-infection and the J&J situation have gotten media attention, but that those cases are few among millions of vaccinations. “If you look at the data they are extremely safe, extremely efficacious and make you basically impervious for getting serious disease, hospitalization and death.”

He reiterated that infection after vaccination is extremely rare and when it does happen the host is much less likely to need medical attention and much less likely to pass on the virus to someone else.

Even with vaccinations and mask-wearing, herd immunity will be difficult and eradication probably not attainable. And if herd immunity is to be approached, school-age kids will need to be vaccinated.

“Herd immunity is an important threshold to cross, but what’s more important is getting the high-risk individuals vaccinated so that we still have cases but we don’t have hospitals in crisis,” Mokdad said. “And the vaccines are doing that even with the variants.”
Jim McKay is the editor of Emergency Management magazine.