Adults may soon be more susceptible to 'childhood' diseases

The number of pertussis cases in 2024 will exceed 32,000, the highest in the past 10 years. In California alone, the disease affected 2,000 people between January and October last year.

More than 60 infants under four months of age were hospitalized in the state. One person died.

Whooping cough, or whooping cough, is just the most obvious example of what happens when vaccination rates drop. But that's not all.

Pediatric immunizations have been suspended across the country due to the pandemic, and vaccination rates have yet to recover. As a result, hundreds of thousands of children are increasingly susceptible to diseases that were once largely relegated to the history books.

Most of them, such as measles, mumps, and rubella, primarily affect young children. But experts say if vaccinations continue to decline over the next few years, due in part to rising mistrust and stricter federal policies, preventable infections will return to form among all age groups.

“It might take a year or two, but there's no question about it,” said Pejman Rohani, an infectious disease epidemiologist at the University of Georgia.

“There will be an outbreak,” he said.

It's not just the unvaccinated people who have to worry. Even adults who were vaccinated decades ago may be susceptible to diseases that are now considered childhood illnesses.

Dr Alex Richter, a clinical immunologist at the University of Birmingham in the UK, said most people had forgotten the dangers of childhood diseases, and the university has seen a worrying rise in measles and mumps cases.

Just a few decades ago, many children under the age of five died from infectious diseases. Today, children are at greater risk of car accidents, drug overdoses, and gun violence, but disease is less of a concern.

“If we don't continue our vaccine policy, everything could change,” Dr. Richter said.

High vaccination rates in the region are due not only to vaccine recipients, but also to people who cannot receive some vaccines due to certain medical conditions, age, weakened immunity, etc., or who may not respond to vaccines. also protects

If fewer people get vaccinated, Dr. Richter said, “we are making an active decision to make the world less safe for a significant portion of the population.”

For example, rubella or rubella can be dangerous for pregnant women and their babies. However, pregnant women cannot be vaccinated against this disease because the vaccine contains live, attenuated virus.

These days, they are usually not at risk, since there are less than a dozen cases of rubella in the United States each year. The situation may change if vaccination rates decline. Globally, rubella is the leading cause of vaccine-preventable birth defects.

“If a mother who is not immune gets rubella, she will suffer lifelong blindness, hearing loss, and all sorts of other complications,” Dr. Richter said.

Elsa Sujuneson knows this all too well. Her mother contracted rubella during her pregnancy during the 1985 New York City outbreak, and Sujunneson was born with congenital rubella syndrome (CRS).

In her case, that meant thick cataracts, hearing loss, and a heart defect.

Before her first birthday, she underwent two surgeries that almost fixed her heart defect, but seven eye surgeries that never fully restored her eyesight. did. She is blind in her right eye, has limited vision in her left eye, and still requires hearing aids.

“Actually, I was really lucky. Many people born with CRS don't survive,” said Soo Jun Naeson, a disability advocate and rubella vaccination advocate. “People don't deserve to be exposed to a potentially deadly disease.”

Anti-vaccine campaigns often target the MMR vaccine, which protects against measles, mumps and rubella. Experts are most concerned about the recurrence of measles.

The virus is highly contagious and can remain in the air for up to two hours after an infected person leaves the room. One infected person can spread the virus to up to 18 other people.

The past shows signs of this. In the late 1980s, budget cuts by the Reagan administration led to lower vaccination rates, especially among low-income black and Hispanic children.

The collapse was rapid. From 1989 to 1991, measles infected more than 55,000 Americans and caused 166 deaths.

Before the introduction of the first measles vaccine in the 1960s, measles killed an estimated 2.6 million people worldwide each year. Viruses disable immune defenses and leave the body vulnerable to other pathogens.

A 2015 study estimated that before widespread vaccination, measles may have accounted for half of all infectious disease deaths in children. Even now, the effects can be severe. According to the CDC, about 40% of those infected last year were hospitalized.

Before the pandemic, MMR and pertussis immunization rates were stable at around 95%, in part because of public school admission requirements.

The decline during the pandemic was not surprising. However, even as society returned to normalcy, vaccination rates continued to decline, dropping below 93% nationwide in the 2023-24 school year.

This means around 280,000 school children remain vulnerable to these diseases, increasing the risk of outbreaks occurring in schools and other public places.

Of course, unvaccinated adults are also at risk, but so are those who don't develop an adequate immune response to the vaccine or who have only received one dose.

And the decline in vaccination rates has another unforeseen effect.

Immunity induced by some vaccines can be lost over decades. This decline means that even vaccinated adults may be more susceptible to certain diseases if outbreaks occur more frequently.

For example, in rare cases, the immunity provided by the measles vaccine may be weakened. Of the 284 measles cases recorded among Americans last year, 11% were in people who had received one or two doses of the vaccine.

This may help explain why 27 percent of cases were in adults over 20 years old.

“We have moved on from the days when measles only affected children,” said Alexis Robert, a research fellow in infectious disease modeling at the London School of Hygiene and Tropical Medicine.

Immunity to mumps may also be reduced. Vaccination has reduced mumps cases by 99% overall, but outbreaks are occurring in schools and universities where students come into close contact with each other for extended periods of time.

Mumps often causes mild symptoms in children, but it can cause fertility problems in boys and severe complications in adults.

The disease may initially be mistaken for a typical respiratory infection, but it can develop into a painful, systemic “100-day cough.” Coughing attacks always end with a whistling sound and can cause vomiting, cracked ribs, and difficulty breathing.

Decades ago, vaccines relied on whole cells of the bacterium that causes whooping cough. It was powerful but harsh, often causing high fevers and seizures.

Dr. Kathryn Edwards, a vaccine expert who has studied whooping cough for 40 years, said: “There is no way that a parent would tolerate such a reaction at this point, it's just not possible.”

Newer versions of the vaccine introduced in the 1990s are much easier on the body. For most people, this preparation provides decades of protection against serious illness.

However, the new whooping cough vaccine does not completely prevent infection, and in some cases the protective effect may wear off.

Experts now believe this is one reason why more adolescents than young children were infected with pertussis during recent pertussis outbreaks.

“This was really the first hint” of vaccine immunity waning, Dr. Edwards said. The CDC currently recommends booster vaccinations for adolescents.

Even if vaccination rates drop to 75% in the next few years, older people who receive the vaccine first may still be protected.

However, people who have never been vaccinated or adults who received a new vaccine as a child may be susceptible.

Epidemiological modeling by Dr. Rohani and his colleagues suggests that the most dramatic increases in cases will occur among infants, who are too young to be fully vaccinated, and children between the ages of 5 and 15.

Dr. Rohani said school-age children are the “core transmission group” because they tend to have the most contacts.

He and other experts said they hope vaccination rates don't drop sharply and are concerned about the impact of even a small drop.

Dr. Richter said vaccines are always harder to sell than treatments because they are given to healthy people.

In very rare cases, serious side effects can be fatal.

“All it takes is one or two of these stories to have a big impact on vaccine rollout,” she says. “There's a tension here between the community and the individual.”