Human factors
Human behavior will also help determine the course of the pandemic, he noted. Vaccine hesitancy, for example, is still high in the United States.
By the end of May, he predicted, about 180 million people will have received about two doses of vaccine. After that, he said, “vaccination will flatline due to lack of demand.” The two unknowns are how much campaigns to promote vaccination will increase vaccine confidence, and when children will be vaccinated.
In the United States, he said, 69% of adults have been vaccinated or want to get a shot. But that percentage has dropped 5 points since February, and vaccine confidence varies by state.
Dr. Murray emphasized that the winter surge he predicts can be blocked if people change their behaviors. These include a rise in vaccine confidence to 80% and continued mask wearing by most people.
However, if vaccine confidence and mask wearing decline, state governments continue to drop social distancing rules, and the uptake of boosters is low, the winter surge could be more serious, he said.
Double surge
Murray also raised the possibility of a double surge of COVID-19 and influenza this winter. Widely expected last winter, this double surge never materialized here or elsewhere, partly because of mask wearing. But Dr. Murray said it could happen this year: History shows that the flu tends to be stronger in years after weak outbreaks.
He advised hospitals to prepare now for whatever might come later this year. Public health authorities, he said, should speed up vaccination, monitor variants closely with additional sequencing, and try to modify behavior in high-risk groups.
Asked to explain the recent surge of COVID-19 cases in Michigan, Dr. Murray attributed it partly to the spread of the B.1.1.7 (U.K.) variant. But he noted that the U.K. variant has expanded even more widely in some other states that haven’t had an explosive surge like Michigan’s.
Moreover, he noted, Michigan doesn’t have low mask use or high mobility. So the upward spiral of COVID-19 infections there is very concerning, he said.
In regard to the role of children as reservoirs of the virus, Dr. Murray pointed out that views on this have changed around the world. For a while, people thought kids didn’t spread COVID-19 very much. That view shifted when U.K. data showed that child transmission of the B.1.1.7 variant increased by half to 9% of contacts in comparison with the original virus strain.
Dutch data, similarly, showed schools contributing to the latest outbreaks, and some European nations have closed schools. In the United States, the trend is to open them.
A version of this article first appeared on Medscape.com.