New preliminary data adds real-world evidence that coronavirus vaccines can reduce severe COVID-19 cases on a national scale, according to a report released Friday from the Centers for Disease Control and Prevention.
In about three months, the Pfizer-BioNTech COVID-19 shot lowered the need for mechanical ventilation among people 70 and older by 67%, compared to those younger than 50. The study was conducted in Israel, which has the highest per capita vaccination rate in the world.
The findings align with results from clinical trials, and add promising evidence that the shots work among real-world populations — a scenario that could not have been tested in controlled lab settings.
And because both currently authorized COVID-19 vaccines in the U.S. offer similar levels of protection against the coronavirus, the report suggests the same benefits apply to the Moderna shot, too.
Still, the vaccines do not prevent against coronavirus infection, but rather severe disease and death, although data indicate the shots make it less likely that an infected vaccinated person will spread the virus to others.
“Considering the vaccination rate and the expected vaccine efficacy, this study provides preliminary evidence at the population level for the reduction in risk for severe COVID-19, as manifested by need for mechanical ventilation, after vaccination with the Pfizer-BioNTech COVID-19 vaccine,” the CDC said in the report.
“These data are consistent with preliminary reports showing a reduction in COVID-19 cases and severe cases in the vaccinated population and a reduction in viral load in vaccinated persons compared with that in unvaccinated persons.”
Israel began a national vaccination campaign on Dec. 20, focusing heavily on people older than 60, health care workers and those with underlying medical conditions. By February, about 84% of people 70 and older had received both doses.
By comparing the group with the highest vaccination rates to the group with the lowest (about 10% of people younger than 50), researchers were able to analyze how well the Pfizer vaccine prevented severe COVID-19.
The initiation of mass vaccination was followed by a strict national stay-at-home order beginning Jan. 8, according to the report, joining school closures, restrictions on commercial activity and travel, and mask mandates.
From October-December 2020 to February 2021, the need for mechanical ventilation in people 70 and older dropped by 67%, compared to people younger than 50. This drop became apparent about the time second doses began being administered on Jan. 10.
The CDC said this might “reflect the effects of the first dose” as shown during Pfizer’s Phase 3 clinical trial in laboratory settings. The results showed one dose of the Pfizer vaccine offered “partial” protection.
The U.S. is fourth in line after Israel,// the United Arab Emirates and the United Kingdom in total COVID-19 vaccinations per 100 people, according to Our World in Data.
More than 46 million Americans have received one dose of a COVID-19 vaccine as of Feb. 25 — nearly 14% of the U.S. population, a CDC tracker shows. More than 21.5 million have been jabbed with a second, final dose.