ST. LOUIS — Missouri COVID-19 case numbers and local hospitalization rates, stuck on a plateau for much of the spring, have begun to dip over the past few weeks, leading some health experts to express hope for the coming months.
“We don’t, at this point, have as many people vaccinated as we would like,” said Dr. Sarah George, associate professor of infectious diseases at St. Louis University. “That concerns me, because the virus is still out there.”
Missouri’s seven-day average of new confirmed cases on Tuesday was 287, the lowest level the state has seen since June 22, 2020, according to a Post-Dispatch analysis. The state reported 690 hospitalized COVID-19 patients statewide, less than a quarter of the number hospitalized at the peak in late December.
Garza said the recent decline in admission numbers looks promising. And with the vaccines, even if cases increase, it is unlikely that the region would see surges as large as those last summer and fall.
The warmer weather over the summer may also help. People will spend more time outdoors, where there is more airflow, and respiratory viruses tend to be more transmissible in cold, dry weather. Health care institutions will continue to roll out vaccines, which are now available for all residents 12 years and older.
In Missouri, 39.8% of the population have received at least one dose of vaccine, and 33% have been fully vaccinated, according to data from the Department of Health and Senior Services.
St. Louis County is above the state average, with 34.5% of the population fully vaccinated, and St. Louis is lower, at 26.9%.
“Every day, people are still getting vaccinated — it’s just not at the rate we’d like it to be,” Garza said.
Earlier this year, the task force projected that, if vaccinations in the St. Louis region continued at a rate of about 43,000 first doses administered per week, 75% of local adults could have at least one dose by late August.
But vaccinations have slowed markedly since then. The state on Tuesday reported a seven-day average of 18,400 vaccinations, down from a peak of 50,000 on April 14.
Garza said he thinks, at the current rate, 60% to 70% of residents could be immunized by the late summer or early fall. And if employers or schools begin to require vaccinations, that could accelerate.
“I think really the open question is: What happens in fall, when it starts getting cooler and people start moving indoors, and the respiratory viruses start circulating?” Garza said. “A lot of that will depend on how many people out in the community have absolutely no protection at all.”
Dr. Steven Lawrence, an infectious disease expert at Washington University, said the seasonality of COVID-19 is not clear. Last year, local COVID-19 hospital admissions were relatively low in May and June, and rose in late summer. Within the first year or two after a new respiratory virus emerges, it generally follows less of a seasonal pattern, because so many people are susceptible to it.
“Once there’s more immunity built up in the population, those seasonal trends really become much more prominent,” Lawrence said. “This is very closely related to other coronaviruses that have very, very clear seasonality.”
Lawrence said the region is seeing positive results, but there is still risk, because not enough people have been vaccinated.
“We still have to be cautious. We still are moving in the right direction,” Lawrence said. “We’re not there yet. But we’re getting closer.”
Editor's note: This story has been updated to correct the title for Dr. Sarah George, associate professor of infectious diseases at St. Louis University.