How many lives have coronavirus vaccines saved? We used state data on deaths and vaccination rates to determine – .

How many lives have coronavirus vaccines saved? We used state data on deaths and vaccination rates to determine – .


More than 200 million U.S. residents have received at least one injection of a COVID-19 vaccine in hopes the vaccines will slow the transmission of the virus and save lives.

Researchers know the effectiveness of vaccines from large-scale clinical trials, the gold standard for medical research. The studies found that the vaccines were very effective in preventing severe COVID-19 and particularly effective in preventing death. But it’s important to follow any new treatment in the real world, as the benefits of vaccines at the population level may differ from the effectiveness found in clinical trials.

For example, some people in the United States have only received the first injection of a two-shot vaccine and are therefore less protected than a fully vaccinated person. Alternatively, people who are vaccinated are much less likely to transmit COVID-19 to others, including those who are not vaccinated. This could make vaccines more effective at the population level than in clinical trials.

I am a health economist and my team and I have studied the effects of public policy interventions like immunization on the pandemic. We wanted to know how many lives vaccines could have saved thanks to state vaccination campaigns against COVID-19 in the United States

Build an accurate model

In March 2021, when weekly data on state COVID-19 vaccinations began to be reliably available from state agencies, my team began to analyze the association between vaccination rates of State and subsequent cases and deaths of COVID-19 in each state. Our goal was to build a model precise enough to measure the effect of vaccination in the complex web of factors that influence deaths from COVID-19.

State data on vaccination rates and deaths from COVID-19 may shed light on the true effectiveness of vaccines.
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To do this, our model compares the incidence of COVID-19 in states with high vaccination rates versus states with low vaccination rates. As part of the analysis, we controlled for things that influence the spread of the coronavirus, such as state-to-state differences in weather and population density, seasonal changes in social behavior, and non-response. pharmaceuticals like stay-at-home orders, hide warrants and business closures overnight. We also took into account that there is a delay between when a person is first vaccinated and when their immune system has developed protection.

Vaccines have saved lives

To check the strength of our model before playing with the variables, we first compared the reported deaths with an estimate produced by our model.

When we gave it all the available information – including vaccination rates – the model calculated that as of May 9, 2021, there should have been 569,193 deaths from COVID-19 in the United States. The number of deaths reported on that date was 578,862, less than 2% difference from our model prediction.

Equipped with our well-functioning statistical model, we were then able to “turn off” the effect of the vaccination and see how much of a difference the vaccines made.

Using near real-time data on state vaccination rates, coronavirus cases, and deaths in our model, we found that in the absence of vaccines, 708,586 people would have died by May 9. 2021. We then compared this to our model estimate of vaccine deaths: 569,193. The difference between these two numbers is just under 140,000. Our model suggests that vaccines have saved 140,000 lives here. on May 9, 2021.

Our study only covered a few months after starting the vaccination. Even in this short period of time, COVID-19 vaccinations have saved thousands of lives despite still relatively low vaccination rates in several states at the end of our study period. I can say with certainty that vaccines have since saved many more lives – and will continue to do so as long as the coronavirus is still around.


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