ST. LOUIS — A data analysis by St. Louis University researchers shows just how much COVID-19 vaccines have prevented infections: The researchers found that, on average, for each additional percent of a county’s population that received a first dose of vaccine, there were four fewer weekly infections.
The data was Monday on the website medRxiv, where researchers post study results of urgent interest, prior to peer review.
Enbal Shacham, a professor at St. Louis University’s College for Public Health and Social Justice, and the lead author, said the analysis has been submitted to an academic journal to be considered for publication.
Shacham said that, while the three COVID-19 vaccine products available in the U.S. have been shown to dramatically reduce infections, the researchers wanted to study the actual relationship between a community’s vaccination rates and its case rates.
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“I think everyone wants to know, if I do something, like get a COVID vaccine, are there actually less cases in my county?†Shacham said. “And, yes. That’s true.â€
The researchers looked at all of the counties and two cities in ÁñÁ«ÊÓƵ over a 25-week period from Jan. 4 to June 26. They used data from the Missouri Department of Health and Senior Services.
One of the most significant findings, Shacham said, was that, even in counties with relatively lower vaccination rates, the vaccines still helped. Those counties did not have to reach a certain threshold of vaccinations before they began to see a benefit.
The data, the authors wrote, suggest that “each person getting vaccinated has an impact.â€
Shacham said that the analysis did not account for other public health measures, like face mask requirements.
Missouri has seen increasing COVID-19 infections since early June, and health officials have tried to spur vaccinations in order to prevent further spread. The state’s seven-day average of new confirmed cases has doubled in less than four weeks, to 706 on Tuesday, from 342 on June 12, according to a Post-Dispatch analysis.
Statewide, 2.7 million people, or about 44.8% of the population have received at least one dose. And of those, 2.4 million people, or 39.3% of the population, are fully vaccinated, according to the state.
The Centers for Disease Control and Prevention said Tuesday 55% of the U.S. is partially vaccinated and 47.5% is fully vaccinated.
COVID-19 in Missouri and Illinois: By the numbers
NOTE: On Thursday, Nov. 18, 2021, the Missouri Department of Health and Senior Services (DHSS) changed how it reports COVID-19 cases and deaths. The department began counting reinfections as new cases, and added epidemiologically linked cases to its counts.
On April 17, 2021, DHSS adjusted a database error that was causing individuals with both a positive PCR and antigen result to be counted as both a probable and confirmed case. This correction removed 11,454 cases that were counted twice in previous probable antigen cases, according the notation. That date's data has been removed from this display.
Beginning March 8, 2021, DHSS began posting county-level data showing "probable" COVID-19 cases detected by antigen testing. Using the historical data from the DHSS dashboard, we reconfigured this graph to include that number in the total.
Missouri updated its data dashboard on Sept. 28. 2020, to delete duplicate cases. This resulted in a decrease of total cases which caused the daily count to reflect a negative number. That date's data has been removed from this display.
NOTE: On Thursday, Nov. 18, 2021, the Missouri Department of Health and Senior Services (DHSS) changed how it reports COVID-19 cases and deaths. The department began counting reinfections as new cases, and added epidemiologically linked cases to its counts.
On April 17, 2021, DHSS adjusted a database error that was causing individuals with both a positive PCR and antigen result to be counted as both a probable and confirmed case. This correction removed 11,454 cases that were counted twice in previous probable antigen cases, according the notation.
Beginning March 8, 2021, DHSS began posting county-level data showing "probable" COVID-19 cases detected by antigen testing. Using the historical data from the DHSS dashboard, we reconfigured this graph to include that number in the total.
Missouri updated its data dashboard on Sept. 28. 2020, to delete duplicate cases. This resulted in a decrease of total cases which caused the daily count to reflect a negative number.
NOTE: On Thursday, Nov. 18, 2021, the Missouri Department of Health and Senior Services (DHSS) changed how it reports COVID-19 cases and deaths. The department began counting reinfections as new cases, and added epidemiologically linked cases to its counts.
NOTE: On Oct. 11, Missouri announced that a database error had resulted in an “incorrect inflation†of cases in its Oct. 10 report
Note from St. Louis Metropolitan Pandemic Task Force: The data includes patients at BJC HealthCare, SSM Health and St. Luke's Hospital. As of Jan. 17, 2022, the data includes patients at the VA St. Louis Healthcare System.
Note from Missouri Department of Health and Senior Services: Note: Due to an abrupt change in data measures and the reporting platform issued by the White House on Monday, July 13, and effective Wednesday, July 15, Missouri Hospital Association (MHA) and the State of Missouri were unable to access hospitalization data during the transition. .
NOTE: On Thursday, Nov. 18, 2021, the Missouri Department of Health and Senior Services (DHSS) began counting probable death along with confirmed deaths.
