Widespread Claims Misrepresent Effectiveness of COVID-19 Vaccines

SciCheck Digest

As the virus that causes COVID-19 has evolved, the vaccines have become less effective in preventing symptomatic infection while remaining highly effective in preventing severe disease and death. This shift has been misrepresented by anti-vaccine influencers who falsely claim that it means the vaccines don’t work and have been ineffective all along.

How effective are the vaccines?

All of the authorized and approved vaccines are effective at preventing severe COVID-19.

Against earlier forms of the coronavirus, the vaccines were highly effective at preventing symptomatic illness. For example, the Pfizer/BioNTech vaccine, which was the first COVID-19 vaccine to receive full approval from the Food and Drug Administration, showed a final efficacy of 91% against symptomatic illness in its phase 3 trial, meaning that under the conditions of the trial the vaccine reduced the risk of getting sick by 91%.

The Moderna vaccine showed similar results in its clinical trial, with a final efficacy of 93%. It has also received FDA approval.

Johnson & Johnson, which partly tested its vaccine in South Africa when the beta variant emerged, reported an efficacy of 66% in preventing moderate to severe COVID-19 and an efficacy of 85% in preventing severe or critical COVID-19 in its clinical trial.

Subsequent studies have demonstrated that the vaccines are effective under real-world conditions, including against the highly contagious delta variant. Against omicron, however, the vaccines haven’t fared as well and are much worse at preventing infection or mild disease. The shots are still good at preventing hospitalization or death, though, particularly if someone has received a booster dose.

Booster shots are recommended for most people, as these increase and prolong protection against severe disease and also provide some temporary protection against infection and milder illness. For instance, a Centers for Disease Control and Prevention study found that during the omicron wave, adults who had received two doses of the Pfizer/BioNTech or Moderna vaccines had a 79% lower risk of dying or needing a ventilator if hospitalized with COVID-19, compared with unvaccinated adults. Those who had received a booster vaccine dose as well had a 94% lower risk.

People over the age of 50 and people who are immunocompromised are also eligible for a second mRNA booster.

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Viruses mutate, or change, as they replicate. That’s largely why the currently available vaccine formulas aren’t working as well at preventing infection with the virus that causes COVID-19.

Those vaccines — made by Moderna, Pfizer/BioNTech and Johnson & Johnson — were highly effective in preventing both symptomatic infection and serious illness against early strains of the virus. But they are less effective against infection from the currently circulating subvariants of the omicron variant.

Public health officials have acknowledged this shift and changed their advice accordingly, in an effort to deal with a disease that became the third-leading cause of death in the U.S. in 2020 and 2021 and has killed more than a million people across the country.

But anti-vaccine campaigners and those who have cast doubt on the severity of COVID-19 have twisted those remarks to suggest that the health care establishment had given faulty advice about the value of the vaccines from the beginning.

For example, conservative influencer David Harris Jr. — who has 1.5 million followers on Instagram — posted a pair of video clips featuring Brett Sutton, the chief health officer for the Australian state of Victoria. One clip is from April, showing Sutton encouraging people to get a booster shot, saying that it can help keep people from “getting infected in the first place.” The other clip shows part of a press conference from August, as Victoria was experiencing a surge in cases, where Sutton said: “Despite two, three, four doses of the vaccine, it’s not so good at preventing infection in the first place.”

Harris didn’t include the dates of the clips — he labeled them only “Then” and “Now.” In the caption, he referred to his earlier claim that the COVID-19 vaccine “doesn’t work,” writing: “I wonder which of my other conspiracy theories will be proven true next???”

Similar claims have been ubiquitous on social media and beyond. They’ve been posted on platforms such as the right-wing website Gateway Pundit, which claimed in a headline that the Centers for Disease Control and Prevention “finally admits their vaccines do not prevent anyone from getting or spreading the virus.”

And they’ve shown up on a San Diego television station that has a history of promoting dubious claims about COVID-19. The station featured a guest who claimed the CDC had said of the vaccines, “turns out they don’t really work anyway,” and that CDC officials “knew they weren’t really going to do what we said they would.”

That guest was Dr. Kelly Victory, who holds an active medical license in both Colorado and Ohio, but according to her LinkedIn profile has spent the last 16 years as a consultant for disaster preparedness training. She also campaigned against the Affordable Care Act in 2012.

Victory has advocated against most public health advice over the course of the pandemic, claiming that “masks don’t work” and that asymptomatic spread “simply doesn’t occur with respiratory viruses.” In one talk radio appearance in 2021, Victory said that she had been “censored” for making those claims. But her claims just aren’t true.

Other related claims have been pervasive online, such as the meme shared by Donald Trump Jr. suggesting that recently updated guidance from the CDC matches what those who have downplayed the severity of the pandemic and questioned the value of the vaccines had been saying all along.

But the new guidance doesn’t indicate that health care experts were wrong about the vaccines or any other mitigation measures they had recommended.

Highly Effective Against Initial Outbreak

“The truth is, the effectiveness of vaccines shifted with each of the new variants,” Dr. Peter Hotez, dean of the National School of Tropical Medicine at Baylor College of Medicine, told us in a phone interview.

When the vaccines were approved for emergency use in 2020, they were approved based on their demonstrated ability to prevent symptomatic illness, he said. And large clinical trials showed that the efficacy was high.

For example, the updated trial results reported to the Food and Drug Administration for full approval showed the Moderna vaccine was 93.2% effective in preventing symptomatic disease at least two weeks after the second dose in people 18 years of age and older.

The vaccines were also highly effective when they were first introduced to the public in the real world.

“The initial SARS-CoV-2 that we had, that initial wild type, the vaccine against it did work against infection,” Dr. Rochelle Walensky, director of the CDC, said in a recent interview on Fox News. “It worked actually quite well against infection. It also worked against severe disease and death.”

A promising early study from Israel showed that the vaccines had been more than 90% effective in preventing both symptomatic illness and asymptomatic infection in the early days after the rollout.

“That was really exciting because it meant that, maybe, we could vaccinate our way out of this pandemic,” Hotez said.

After the first variant, alpha, emerged, the vaccines remained highly effective against infection, severe disease and death, Walensky said.

In May 2021, the CDC said that those who were fully vaccinated could stop wearing masks.

Then the virus mutated, and the delta variant became dominant in the summer of 2021.

Recommendations Evolved With Variants

Although the vaccines remained effective against severe illness and death from COVID-19, they were somewhat less effective at preventing infection from delta.

That’s when the CDC reversed its recommendation and said that those who were vaccinated should wear a mask indoors.

That fall, the Biden administration made booster shots available.

The virus keeps changing, and subvariants of omicron are now dominant. It’s become increasingly clear that the vaccines are less effective in preventing infection than they had been with earlier variants.

This is due to two things, Hotez said — changes to the virus and the natural decline in the potency of vaccination over time, which happens with most vaccines.

The CDC noted the waning effect of immunity from the vaccines in an August report explaining the most recent changes to its guidance on COVID-19 prevention, which included a recommendation for booster doses.

“Overall booster dose coverage in the United States remains low, which is concerning given the meaningful reductions in risk for severe illness and death that booster doses provide and the importance of booster doses to counter waning of vaccine-induced immunity,” according to the paper, which was published in the CDC’s Morbidity and Mortality Weekly Report on Aug. 11.

It also noted that the vaccines are “highly protective” against severe disease and death, and that they offer “minimal protection against infection and transmission.” That last part is what Victory and others highlighted, while neglecting to mention how effective the vaccines are against serious illness.

Victory claimed that the CDC had “acknowledged” that the vaccines were “essentially ineffective.”

But that’s not accurate.

As we said, the CDC explained that being up to date with vaccination offers minimal protection from infection, but, importantly, significant protection against severe disease. Being up to date with vaccination means that you’ve gotten the primary series of doses and any boosters that are available for your age group, the CDC has explained.

“Being up to date with vaccination provides a transient period of increased protection against infection and transmission after the most recent dose, although protection can wane over time,” the CDC said. The rates of hospitalization and death are “substantially higher” among unvaccinated adults, especially those 65 and older, compared with those who are up to date with vaccination, the CDC also said.

In fact, data from the COVID-19 Associated Hospitalization Surveillance Network for March 20 through May 31, 2022, showed: “Hospitalization rates among unvaccinated adults were 3.4 times as high as those among vaccinated adults,” according to an Aug. 26 CDC report.

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