Vaccines and trust are key to preventing COVID deaths, study finds

The United States has a dubious reputation for having the highest COVID-19 death rate among high-income countries in the world. But that national average — 372 deaths per 100,000 people last summer — hides the fact that the impact of the pandemic has varied greatly from state to state.

In a comparison that accounted for demographic differences between states, Arizona’s COVID-19 death rate, at 581 deaths per 100,000 people, was almost four times higher than Hawaii, which had 147 deaths per 100,000 people. Death rates in the hardest-hit US states were similar to countries without any health infrastructure. States that did best had rates on par with countries like Australia, New Zealand and South Korea, which were working assiduously to keep the pandemic death toll down.

What explains these big differences? A new study offers some intriguing answers.

Race, ethnicity and socioeconomic factors were the strongest predictors of a state’s COVID-19 death toll, according to researchers. The greater the proportion of residents who identified as Black or Latino, the higher the poverty rate, the greater the proportion of residents without health insurance, and the lower the adult education level, the more deaths per capita.

That might not come as a big surprise. But the researchers also found that the more people in a state trust each other, the lower the collective risk of dying from COVID-19. This finding underscores how America’s growing divisions have seemingly made us uniquely vulnerable during the pandemic.

“How we feel about each other is important,” said political scientist Thomas J. Bollyke, one of the study’s lead authors. “Solidarity between people—the sense that if you don’t take advantage of what’s right, others will do the right thing—is a big driver of your willingness to embrace protective behavior.”

The report, published last week in the medical journal Lancet, is based on a wealth of US pandemic data from January 2020 to July 2022. Bollyke called the company “the most comprehensive statement yet on the drivers of the pandemic’s impact”.

Numerous researchers from across the country extracted data on the demographics of states before the pandemic, looking for ways in which their behavior and policies differed over the course of the pandemic. To make direct comparisons between states, they created standardized measures of infection and death rates that accounted for differences in COVID-related factors such as residents’ age and underlying health conditions.

A map comparing cumulative COVID-19 mortality rates by state, standardized to account for differences in residents’ ages and underlying health conditions.

(Bollyky et al., The Lancet)

For example, California’s unadjusted rate of 291 COVID-19 deaths per 100,000 people was lower than all but 11 other states. But once the research took into account that the state has a relatively young population with a low prevalence of diseases that people are susceptible to making severe cases of COVID-19, the death rate rose to 418 deaths per 100,000 people. Only 15 states fared worse, the study authors found.

Demographics only told part of the story. Political decisions also played a role.

Most states adopted some form of masking and social distancing mandates early in the pandemic, but there were big differences in how strict they were and how long they lasted. When the researchers assigned each state a “mandate propensity,” they found that states that scored high on adopting public health measures had lower coronavirus infection rates.

California had the highest mandate propensity while Oklahoma had the lowest. The researchers calculated that if Oklahoma had adopted masking and social distancing restrictions at the same rate as California, Oklahoma would have seen 32% fewer coronavirus infections.

However, more aggressive public health mandates did not result in lower death rates. The authors suggest this is likely because many older and sicker people, who are most likely to die if infected, have taken steps to protect themselves, whether or not their state governments enacted strict rules.

The researchers also found that a state’s propensity for mandates has no impact on the health of its economy, as measured by gross domestic product. While states with less mask use and fewer restaurant closures had higher employment levels, this additional economic activity came at a price: Every one percentage point increase in a state’s employment was associated with 143 additional deaths per 100,000 people.

No single factor was more important than “days of people vaccinated” – a measure of how much of a state’s population was vaccinated and how early. If Alabama, which had the lowest score on this measurement, had matched the immunization coverage seen in Vermont, the highest-ranking state, there would have been 30% fewer infections and 35% COVID-19 deaths over the study period, they estimated researcher .

Another notable finding: Vaccination orders for government employees, which led to many legal challenges, “stand out” for their association with fewer infections and fewer deaths, the authors wrote.

A map comparing cumulative rates of coronavirus infection by state, standardized to account for differences in population size.

(Bollyky et al., The Lancet)

The study highlights the palpable toll of the country’s us-versus-them mentality, which was on full display during debates over masking in schools and vaccination requirements for government employees. We don’t trust each other very much, which makes us less willing to do things to protect each other.

“Interpersonal trust” has been measured since the 1950s, and the level of this positive feeling toward others has declined sharply in the United States since the early 1990s, said Bollyke, who directs the global health program at the Council on Foreign Relations. This trend has been fueled by deteriorating economic conditions for those with lower incomes and higher education qualifications. It is particularly low among black Americans and among those who voted for Donald Trump in the 2020 election.

Trust in the federal government and trust in science were not registered as the main drivers of COVID-19 death rates. But trust in fellow citizens held strong, Bollyke said.

The associations uncovered in the study clearly suggest that the strengths and weaknesses that states take with them in a national emergency — and some of the strategies they employ to respond to a crisis — make a big difference, Lawrence Gostin said, Public health law expert at Georgetown University.

“This is a powerful endorsement for states that have taken COVID seriously, harnessed science and reduced health inequalities,” Gostin said. “A lot of the political rhetoric – that mandates don’t work and that justice doesn’t matter – has just been proven wrong.”

The results of the study can be used to save lives long before the next pandemic, said Dr. Steven Woolf, a researcher at Virginia Commonwealth University who tracks the health of Americans.

“Many of the same factors are impacting health outcomes right now,” Woolf said.