Vaccine Protection Dipped As Delta Surged For Frontline Workers: CDC

Stat: As Delta Spread, Covid Vaccine Effectiveness Against Infection Fell To 66%
The effectiveness of Covid-19 vaccines at preventing infection fell in one study of U.S. frontline workers from roughly 90% to 66% as the Delta variant emerged and became dominant in the country, an updated report from the Centers for Disease Control and Prevention released Tuesday indicated. The study, known as HEROES-RECOVER, includes more than 4,000 health care workers, first responders, and other frontline workers in eight locations across six states, all of whom have been tested weekly for infection with SARS-CoV-2. More than 4 in 5 were vaccinated, and the vast majority of them received the mRNA vaccines from either Pfizer-BioNTech or Moderna. (Joseph, 8/24)

The New York Times: Vaccines Prevented Fewer Infections As Delta Emerged, Researchers Find
Coronavirus vaccines provided strong protection against infection for essential workers earlier this year, but became less effective as the highly contagious Delta variant became the dominant form of the virus, according to a study published on Tuesday by federal health officials. It was not clear whether the decline in protection was caused by the emergence of the Delta variant or the lengthening period of time since the inoculations were begun. Vaccine effectiveness showed possible signs of decline starting four months after vaccinations were first rolled out. (Caryn Rabin, 8/24)

Bloomberg: Covid Vaccine Efficacy Declined In Frontline Workers After Delta Variant
The effectiveness of Covid-19 vaccines among front-line workers declined to 66% after the delta variant became dominant, compared with 91% before it arose, according to a report from the U.S. Centers for Disease Control and Prevention. The vaccines are still protective, the CDC said, and the finding must be interpreted with caution, as vaccine effectiveness might wane over time and the estimates of efficacy were imprecise. (Tozzi, 8/24)

In similar research from the U.K. —

Reuters: COVID Jab Protection Wanes Within Six Months - UK Researchers
Protection against COVID-19 offered by two doses of the Pfizer/BioNTech and the Oxford/AstraZeneca coronavirus vaccines begins to fade within six months, underscoring the need for booster shots, according to researchers in Britain. After five to six months, the effectiveness of the Pfizer jab at preventing COVID-19 infection in the month after the second dose fell from 88% to 74%, an analysis of data collected in Britain's ZOE COVID study showed. For the AstraZeneca vaccine, effectiveness fell from 77% to 67% after four to five months. (8/25)

In news on the J&J shot efficacy —

The New York Times: J. & J. Finds That A Second Dose Of Its Vaccine Provides A Strong Boost
A booster shot of the Johnson & Johnson vaccine dramatically raises the levels of antibodies against the coronavirus, the company reported on Wednesday. Johnson & Johnson will submit the data to the Food and Drug Administration, which is evaluating similar studies from Pfizer and Moderna. If authorized by the agency, the Biden administration wants to provide booster shots eight months after vaccination. The Johnson & Johnson vaccine was absent from the government’s initial booster plan, announced last week. But with the new data, the company hopes to be part of the initial distribution of additional shots, which could happen as early as September. (Zimmer, 8/25)

ABC News: J&J Vaccine Booster Shot Raises Antibody Levels 9-Fold, Company Says
In the midst of a delta variant surge, a new study finds that giving a booster dose of the Johnson & Johnson shot six months after primary vaccination results in a nine-fold increase of a crucial antibody response, according to a company press release. Meanwhile, a prior study found that people vaccinated with the Johnson & Johnson vaccine still had a durable immune response at least eight months later, even without a booster. (Salzman, 8/25)

On hopes for vaccine efficiency —

Stat: Covid-19 Vaccines Flirted With Perfection. Reality Is More Complicated
When Covid-19 vaccines were reported last fall to be roughly 95% effective at preventing symptomatic Covid-19 infections, the world rejoiced — and even veteran scientists were blown away. Very few vaccines are that protective. Those made to fend off viruses like SARS-CoV-2 — viruses that invade the nose and throat, like flu — typically aren’t at the high end of the efficacy scale. That was the good news. Now, however, our soaring expectations for Covid-19 vaccines are in the process of sinking back to earth. (Branswell, 8/25)

Meanwhile, from California —

The Washington Post: Coronavirus Vaccines Remain Highly Effective At Stopping Severe Disease Amid Spread Of Delta, L.A. Data Show
Unvaccinated people in Los Angeles County were five times as likely to become infected with the coronavirus and 29 times as likely to be hospitalized as people who were fully immunized, newly released data from California show. It is the latest evidence that vaccines continue to reduce significantly the risk of severe illness — their fundamental purpose — despite the spread of the more contagious delta variant. The report, published Tuesday by the Centers for Disease Control and Prevention, also demonstrates the limits of vaccines. They are not an impenetrable barrier against the virus. Some inoculated people are continuing to develop covid-19, the disease caused by the virus. But the vast majority of “breakthrough” cases among vaccinated people do not require hospitalization. (Achenbach and Nirappil, 8/24)