We're Doctors. Here Are 4 Things Parents Need To Understand About Vaccines.

Chickenpox. Whooping cough. Measles. You may have heard about outbreaks of these illnesses and thought, “Didn’t we end those with vaccinations?”

But the only communicable disease that we have eradicated using vaccines is smallpox, which explains why you likely never received a shot for it if you were born in the U.S. after 1972.

Measles , which infected almost half a million people annually before the vaccination was licensed in 1963, was declared eliminated from the U.S. in 2000, a historic public health achievement. This means that outbreaks happen only when someone brings the virus into the U.S. from another country, which, given the high rate of international travel, does occur.

In 2019, there was a sharp uptick in the number of cases of measles reported in the U.S. ― 1,274 that calendar year. This was the highest number of cases reported in one year since 1992, and the majority of these were among unvaccinated individuals.

So far in 2024, there have been 269 reported cases of measles, including 14 outbreaks (consisting of three or more related cases). Again, the majority of people who got sick (88%) were unvaccinated or their vaccination status was unknown. Forty-one percent were under 5 years old. It makes sense that young children would be most affected, since most babies do not receive their first dose of the MMR (measles mumps rubella) vaccine until they are 12 months old.

This year, whooping cough (pertussis) has been in the news. The number of cases has risen to five times that of 2023 rates. However, it should be noted that this increase marks a return to pre-pandemic numbers. Cases of whooping cough dropped dramatically during the pandemic when social-distancing measures were in place. Unlike measles, whooping cough is considered endemic, or common, in the U.S. Though vaccines against whooping cough (DTaP and Tdap) work well, their effectiveness wanes over time, meaning that older children may be able to spread the disease again if they do not receive booster shots. (Note that it is recommended that pregnant people receive a vaccine in order to provide their infant with short-term protection from the illness.)

Vaccines are an essential tool when it comes to preventing outbreaks of disease, yet vaccination rates have been going down. From the 2019-2020 to the 2022-2023 school years, the number of kindergarteners who had received all of their recommended vaccines dropped from 95% to less than 93%. The number of students who received exemptions from vaccine requirements also rose from 3% in 2022-2023 to 3.3% in 2023-2024. This is the fourth year in a row that rates have missed the Department of Health and Human Services Healthy People 2030 goal of 95% of kindergarteners having received the MMR vaccine. For measles, experts say that 95% is the rate of vaccination necessary to achieve “herd immunity,” meaning that enough people in the community are vaccinated to protect the minority (such as babies) who are not. (The rate needed to achieve herd immunity is different for other diseases.)

“With declines in routine childhood vaccination, more communities across the U.S. may be at risk for experiencing outbreaks of vaccine-preventable diseases,” Jasmine Reed, a spokesperson for the Centers for Disease Control and Prevention, told HuffPost.

“Vaccination is the best way to prevent these outbreaks and their devastating impact on children,” Reed said.

Some children fell behind on their vaccinations due to the disruptions of the COVID-19 pandemic.

Why are fewer children getting vaccinated?

There are several reasons why vaccination rates in children may be dipping.

First, many children missed routine health care appointments during the pandemic lockdowns. “Some kids fell behind on their vaccines and just never caught up,” Dr. Kris Bryant of Norton Children’s Hospital in Louisville, Kentucky, told HuffPost.

The pandemic may have also altered some parents’ perception of these illnesses. “During the early years of the pandemic, the measures we took to prevent COVID-19 reduced the circulation of other diseases, like flu and whooping cough. Some parents may not know that these diseases can be severe in children and may not perceive an urgency around prevention,” Bryant said.

Access is also an issue for some families. “Vaccine coverage is often lower among children who are covered by Medicaid or other non-private insurance, children living below the poverty level and those who live in rural areas,” Bryant said. It may be that these children’s families are not opposed to vaccines but there are barriers, such as not being able to take time off work, that prevent them from getting children to health care appointments.

Finally, there is a small but vocal group of parents who do not want their children to be vaccinated. These are the families seeking exemptions to school vaccine requirements. Reed noted that the 3.3% exemption rate this year “means over 126,000 kindergarteners have an exemption from at least one vaccination for the 2023-24 school year.” Exemptions increased in 40 states as well as the District of Columbia. In 10 states, more than 5% of kindergarteners had an exemption for at least one vaccine.

Some children, such as those who are immunocompromised, have vaccine exemptions for health reasons. Others seek exemptions for religious or personal (sometimes called “philosophical”) reasons. Rules and regulations vary by state. Though all states allow medical exemptions, only 13 allow for these other options. Some parents also choose to homeschool their children in order to avoid vaccination requirements.

Reed said that in a CDC survey conducted in 2023, “concern about serious side effects was the most common reason reported by parents that they would consider not getting their child a routine vaccine.”

Again, the pandemic may be behind the shift in some people’s thinking about vaccines. “One possibility is that parents’ reluctance related to COVID-19 vaccines may have spilled over to affect confidence about routine vaccines. We may also be seeing a lingering reaction to COVID-19 mandates,” Bryant said.

Though not all of the information people spread about vaccines is trustworthy, the fear that some parents feel is real. Here is what doctors want families to know:

States require students to receive immunizations before they can attend school.

The diseases vaccines prevent can be serious.

Although often mild for older children, whooping cough infections lead to hospitalization in about a third of infants, Bryant said, and can be deadly in this age group.

Complications from measles can be severe. When an unvaccinated person is infected, their odds of hospitalization are about 1 in 5, Bryant said. “One in 20 kids with measles will develop pneumonia, and 1 in 1,000 can develop encephalitis or inflammation of the brain.”

“Measles encephalitis can lead to seizures, deafness and permanent disability. People who recover from measles can develop a deadly brain condition years after the original infection,” Bryant said. Though rare, this condition is thought to be more common in people who get measles before age 2.

Some parents may wonder why they should vaccinate their kids against chickenpox, which was a routine part of childhood in previous generations. But not all children recovered from chickenpox so easily. Before vaccination began in 1995, every year more than 4 million people got chickenpox, 10,500 to 13,500 were hospitalized and 100 to 150 died — half of them children.

Dr. Patricia Pinto-Garcia at GoodRx told HuffPost, “The chickenpox vaccine lowers the chances of a child getting sick. If a vaccinated child does get sick, they experience a very mild illness and are very unlikely to develop any long-lasting complications from chickenpox.”

Vaccines work.

People’s understanding of how effective vaccines are may also have shifted after hearing news reports of COVID-19 vaccines being more or less effective against different strains of the virus. But the recommended childhood vaccines are different from seasonal ones, such as for the flu and COVID-19.

“Most vaccines offered to children are between 90% and 99% effective ,” Pinto-Garcia said. And when vaccinated children do get sick, they are less likely to develop serious complications.

Once a vaccine is introduced, rates of the disease plummet. Cases of chickenpox, for example, have declined by 97% since the vaccine came out in 1995.

Vaccines are safe.

It is not difficult to find frightening stories online from parents who believe their children were harmed by vaccines. But it’s tricky to verify these accounts. There is, however, a large body of scientific evidence that vaccines are safe.

The Vaccine Injury Compensation Program , which provides monetary compensation to people harmed by a vaccine, has adjudicated 12,274 petitions from 2006 to 2022. Of those, 8,904 were compensated. More than 5 billion doses of vaccine were administered in the U.S. during this time, meaning that the likelihood of being compensated for a vaccine injury was approximately 1 in 1 million.

Pinto-Garcia pointed out that you are more likely to get struck by lightning than injured by a vaccine.

The vaccine schedule has been carefully studied .

Other common concerns that vaccine-hesitant parents express involve the number of vaccines and the frequency of their administration.

It’s true that there are now more vaccines on the recommended schedule than when today’s parents were children themselves. Pinto-Garcia compared these to other medical innovations: “Hepatitis B, HPV and meningococcal vaccines are lifesaving vaccines that weren’t available 40 years ago. Millions of people will live longer, healthier lives because of these vaccines.”

Some parents think they can reduce the risks of side effects by delaying or spacing out their child’s vaccines instead of following the recommended schedule. But there is no evidence of this, and there are compelling reasons to stick to the standard schedule.

“The recommended schedule is based on how a child’s immune system responds to vaccines at various ages and how likely a baby is to be exposed to a particular disease,” Reed explained. “Children who are not vaccinated on schedule are not only at risk of getting sick themselves, but they can also spread illness to others who are not protected.”

Some parents worry that children receive “too many” vaccines at once. Single shots, such as DTaP, protect against multiple diseases. But there is no evidence for concern about exposure to multiple vaccines, either.

“The current vaccine schedule is based on research that ensures the highest level of safety and effectiveness. This research has shown that children’s (and adults’) immune systems can handle multiple vaccines without being overwhelmed,” Pinto-Garcia said.

It’s also worth remembering that vaccines are about protecting the whole community, not just your child.

“Babies are particularly vulnerable to life-threatening infections. Before widespread vaccinations, infants and young children were often most affected by these diseases,” Pinto-Garcia said.

A high rate of vaccination is the best way to protect them and other vulnerable populations.

“When the majority of a population is vaccinated, we all safeguard each other,
especially those with weaker immune systems and people not able to get regular vaccines,” Pinto-Garcia said.