SciCheck Digest
Flu shots and vaccines that protect children against measles, mumps and rubella have been effective in preventing illness, serious disease and death. But a meme has been circulating with the false suggestion that those vaccines are ineffective. Actually, they’ve saved millions of lives and have eliminated both measles and rubella in the U.S.
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Public health experts around the world have hailed the widespread use of vaccines as one of the most important medical advances in the last century.
“Vaccines are one of the greatest achievements of biomedical science and public health,” the Centers for Disease Control and Prevention wrote in 1999.
“Immunization currently prevents 3.5-5 million deaths every year from diseases like tetanus, pertussis, influenza and measles,” the World Health Organization wrote in a recent roundup celebrating its 75th anniversary. “As diseases like polio and diphtheria fall out of living memory, people are increasingly vaccinated against diseases they have never seen, making it harder to understand how devastating they can be.”
But while vaccines are responsible for saving millions of lives and preventing even more illnesses, public confidence in vaccination has begun to erode in recent years. During the COVID-19 pandemic, while overall support for vaccines remained high, public perception of the importance of vaccination for children fell in 52 of 55 countries studied by UNICEF. The U.S. was among the countries where it declined.
Anti-vaccine advocates used the pandemic to amplify their message by targeting the new COVID-19 shots and gaining many followers.
“Although anti-vaccine activism was already increasing in the USA and internationally, the 2020 emergence of COVID-19 served as an accelerant, helping turn a niche movement into a more powerful force,” according to a recent paper published in the Lancet.
A meme circulating on social media (shown at right) illustrates how false claims about long-accepted vaccines have become entwined with the campaign against COVID-19 vaccines.
The meme references flu shots and the combined vaccine to protect against measles, mumps and rubella, called MMR, both of which have been available for decades. It falsely suggests that those inoculations don’t work. Social media accounts that have shared the meme also include captions that say things like, “How long will we pretend the COVID vax works?” Another, similar meme focused on the flu shot claim has also been circulating.
This is just the latest version of the well-worn falsehood that the continued spread of COVID-19 proves that the vaccines don’t work. We’ve explained before why that’s wrong. As new variants of COVID-19 emerged, the vaccines became less effective in preventing symptomatic infection, but they are still highly effective in preventing severe disease and death.
This new meme deploys the same deceptive tactic to cast doubt on two other, unrelated vaccines. We’ll address the effectiveness of each vaccine below.
Flu Vaccine
Flu shots were first developed with help from the U.S. Army in the early 1940s and were approved for use in 1945.
Those early shots were effective against only a couple of strains of the influenza virus, though. There are four types of influenza — called A, B, C and D — and the two that are mostly likely to affect humans, A and B, can be broken down into more specific subtypes and lineages.
In order to monitor which of those strains were most prevalent at a given time, the WHO started the Global Influenza Surveillance and Response System in 1952. The GISRS continues that work today in 127 countries, making it easier to target specific strains each year.
“There is often more than one type of influenza virus circulating each season,” the U.S. Food and Drug Administration has explained on its website. “So, vaccines are formulated to target four of the most likely influenza viruses to circulate and cause illness in the U.S. during the upcoming influenza season: two influenza A types (H1N1 and H3N2) and two types of influenza B. These are known as quadrivalent vaccines. Influenza B more commonly affects children and also causes more complications and death in children than adults.”
So, flu vaccines have improved since they were first introduced, and the number of people getting them has increased over time.
According to CDC data, the number of doses administered in the U.S. has risen markedly over the last four decades. In the 1980-1981 flu season, the earliest for which there is data, 12.4 million people were vaccinated. In the 2020-2021 flu season, which was in the midst of the COVID-19 pandemic, a record high 194.4 million people were vaccinated. That high dropped slightly in the following two flu seasons, to 175.6 million in 2021-2022 and 173.4 million in 2022-2023.
Since the 2010-2011 flu season, the CDC estimates that vaccination has prevented nearly 5,500 deaths each season on average, as we’ve explained before, excluding the 2020-2021 flu season since measures adopted to slow the spread of the virus that causes COVID-19 led to far fewer cases of the flu.
So, the flu vaccine clearly works.
However, the meme suggests that flu vaccines aren’t effective because they haven’t eradicated influenza after nearly 80 years and there’s still a need for annual vaccinations.
But that reasoning is flawed for a couple of reasons.
First, not all vaccines are the same. Some require only a primary series to be effective for life (such as the hepatitis B vaccine) and others require new dosages regularly (such as the flu vaccine). This is because the viruses they’re designed to address behave differently.
Long-lasting vaccines typically target viruses that replicate uniformly, Dr. Linda Yancey, an infectious disease expert at the Memorial Hermann Health System in Houston, explained in a post for the hospital.
“They replicate very faithfully, so if you have hepatitis B, every hepatitis B virus in your body looks identical,” she said. “The same with measles. They are very good at replicating themselves without error, and that is a huge benefit for us, because it means that once you get antibodies against one hepatitis B or measles virus, you have immunity against every hepatitis B or measles virus you are ever going to encounter.”
By contrast, the influenza virus shifts frequently.
“The reason we have to get the flu shot every year is that the influenza virus is able to shuffle its chromosomes around in a way that most viruses cannot,” Yancey said.
“This actually happens on a very regular basis, and that’s why, every year, we have to come up with a new flu vaccine depending on the strains currently circulating,” she said.
Scientists are working to develop a universal vaccine for the flu, which would be effective against a broad spectrum of strains, Dr. Anthony Komaroff, a professor at Harvard Medical School, explained in an April post. It would work by targeting a common element shared by most flu strains that’s buried deeper in the structure of the cell instead of targeting structures on the outer layer, as is the case now.
The same thing that necessitates a different formulation for the vaccine each year — the wide variety of strains and their ability to quickly mutate — is also the reason that influenza hasn’t been eradicated.
“[E]ven if we could vaccinate everyone around the world, we would not be able to eradicate influenza,” the American Museum of Natural History explained about the elimination of diseases. “There are many different strains of influenza virus, and they mutate frequently — so new vaccines must constantly be created to keep up. There’s another problem as well: some animals can become infected with different strains of influenza, and these can spread to people and other mammals. Avian flu comes from birds, and swine flu from pigs. Unless we can figure out how to inoculate all birds and pigs, we’ll never be able to stop transmission of the infection.”
And as the CDC has explained, “At least two factors play an important role in determining the likelihood that vaccination will protect a person from flu illness: 1) characteristics of the person being vaccinated (such as their age and health), and 2) how well the vaccines ‘match’ the flu viruses spreading in the community. When flu vaccines are not well matched to some viruses spreading in the community, vaccination may provide little or no protection against illness caused by those viruses.”
MMR Vaccine
Measles was eliminated in the U.S. in 2000 due to widespread vaccination in the preceding decades.
Rubella was eliminated four years later.
While mumps hasn’t yet been eliminated in the U.S., there’s been a 99% reduction in cases since the first mumps vaccine became available in 1967.
Those three vaccines were combined into the common childhood shot called MMR in 1971, which was 52 years ago.
Since the meme refers to a vaccine that’s been available for 60 years, it’s probably talking about the first measles vaccine, which was licensed for use in 1963. So, we’ll focus on the impact of vaccination against measles.
As we said, measles has been eliminated in the U.S., which means that the disease hasn’t spread for a year or more in a specific area. However, unvaccinated travelers may bring it into the U.S. and cause isolated outbreaks in communities with other unvaccinated people.
“By the end of 2021, 76 (39%) countries had been verified by independent regional commissions as having achieved or maintained measles elimination status,” according to the CDC.
The WHO has estimated that measles vaccination has prevented 56 million deaths worldwide between 2000 and 2021.
Although the U.S. has maintained its measles elimination status, there have been some outbreaks in recent years. As we wrote about one such case in 2019, travelers had brought the virus into the country and the disease then spread in communities that have unvaccinated people, according to the CDC.
The CDC issued a statement that April identifying misinformation about the safety of vaccines as a “significant factor” contributing to the outbreak. Similarly, the executive director of UNICEF and the director-general of the WHO issued a joint statement calling measles “the canary in the coalmine of vaccine preventable illnesses.” They, too, cited online misinformation about vaccine safety as a contributing factor in the rising number of measles cases in high- and middle-income countries.
Similarly, an Ohio outbreak in late 2022 was concentrated among unvaccinated patients.
“This outbreak was characterized by young median patient age, low rates of MMR vaccination, and high rates of respiratory coinfection, with twice the hospitalization rate reported among previous measles cases in the United States,” according to a CDC report on the incident. “This outbreak serves as a reminder that health care facilities, medical providers, and child care facilities serving undervaccinated populations should maintain vigilance for measles and emphasize the importance of timely MMR vaccination. Sustaining elimination of measles in the United States will require continued high 2-dose MMR vaccination coverage in all communities.”
So, the suggestion that the MMR vaccine hasn’t been effective is easily disproved. It’s led to the elimination in the U.S. of two of the three targeted illnesses and a steep decline in the third.
Editor’s note: SciCheck’s articles providing accurate health information and correcting health misinformation are made possible by a grant from the Robert Wood Johnson Foundation. The foundation has no control over FactCheck.org’s editorial decisions, and the views expressed in our articles do not necessarily reflect the views of the foundation.
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