State Stay-At-Home Orders May Have Reduced Early COVID-19 Hospitalizations

In at least 4 different states, the execution of legislative stay-at-home orders were associated with deviations from projected best-fix exponential growth rates of coronavirus 2019 (COVID-19) spread in the state.

In other words, experts have found correlation between enforced social distancing and lessened risk of worst-case spread of COVID-19.

A team of Minnesota-based investigators sought to contribute to the understood rate of infected individuals in the US, noting that most studies assessing response measures to this point have relied on confirmed cases or deaths.

The former, they wrote, is a “conservative estimate” to the true COVID-19 infection rate and the latter is a “lagging, insufficient” metric for proactive hospital capacity planning.

“A more valuable metric for assessing the effects of public health interventions on the health care infrastructure is hospitalizations,” the team wrote.

As of April 18, 42 state governments had issued statewide executive stay-at-home orders to help mitigate COVID-19 hospitalization risks—the main intent being avoidance of overwhelmed systems and strained resources.

To understand the association between such state orders and true hospital trends, the investigators began collecting data on cumulative confirmed daily COVID-19 hospitalizations from each state’s department of health website starting in March.

They identified states with both stay-at-home orders and at least 7 consecutive days of cumulative hospitalization data for COVID-19 prior to the stay-at-home order data, as well as data at least 17 days after the order date.

As median COVID-19 incubation period was reported to be 4-5.1 days, and the median time from first symptom to hospitalization was reported as 7 days, investigators hypothesized that any association between stay-at-home orders and COVID-19 hospitalization rates would be evident following 12 days.

Their eligible sample of states included Colorado, Minnesota, Ohio, and Virginia. Earliest hospitalization data was available March 10, and all 4 states were observed April 28.

The team then determined the best exponential growth function to cumulative hospitalization data in each state for dates up to and including the median effective date of that state’s stay-at-home order. Then, the observed cumulative hospitalizations for dates following the median effective date deviated from the projected exponential growth in cumulative hospitalizations was examined.

From the first day of reported data to April 28, state cumulative hospitalizations due to COVID-19 increased as such:

• Colorado: from 2 to 2671
• Minnesota: from 7 to 912
• Ohio: from 17 to 3340
• Virginia: from 19 to 2165

In all of the 4 states eligible and observed, cumulative hospitalizations due to COVID-19 deviated from investigators’ projected best-fit exponential growth rates following the orders becoming effective.

The deviation started 2-4 days sooner than the median stay-at-home effective date in the observed states, which could be due to a median incubation period for symptom onset and time to hospitalization.

That said, investigators queried whether unobserved factors including social distancing guidance, school closures, and general awareness campaigns could have influenced the deviation in the observed states.

“In addition, economic insecurity and loss of health insurance during the pandemic may have also decreased hospital utilization,” they wrote.

The study, “Association of Stay-at-Home Orders With COVID-19 Hospitalizations in 4 States,” was published online in JAMA.