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Why it’s a bad idea to space out your child’s vaccination shots

Avis Meeks Day, a pediatrician at the Austin Regional Clinic, examines a little girl. In 2015, the clinic said it would no longer accept new patients who aren’t getting fully vaccinated. (Austin Regional Clinic and Leindani Creative)

With so many vaccines being required for young children today, some parents are asking their doctors whether they can space out or delay the vaccine schedule. They’re concerned that too many vaccines might overwhelm their child's immune system. Parents also worry that getting more than one shot at a time increases the pain and stress.

Debate about childhood vaccinations has intensified in recent years because of outbreaks of vaccine-preventable disease that have been fueled in part by parents who decline to get their children vaccinated at all or according to the recommended schedule.

After a 2014-2015 outbreak of measles that spread at Disneyland, California passed a law that requires almost all public school children to get immunizations. State health officials announced last week that California's school vaccination rate is now at its highest level in more than 15 years.

Pediatricians and public health experts say parents are continuing to ask questions about the recommended vaccine schedule. Here are some answers to those questions.

Why do kids have to get so many shots at once?

The schedule is designed so that vaccines are given at the earliest possible age at which a child's immune system will respond well. The immune system creates protective antibodies in response to the vaccine that prevent a child from coming down with measles, whooping cough, mumps or other serious infections. The longer a child waits for a vaccination, the greater the risk that he or she will be exposed to these diseases while unprotected.

Isn’t getting all these shots hard on the immune system of such young children?

No. It might seem like your baby is being injected with a lot at once, says Kristen Feemster, a pediatrician and infectious-disease specialist who is research director of the Vaccine Education Center at the Children’s Hospital of Philadelphia. “I know that’s a big concern. But it’s really important to know that what a vaccine is giving your baby is really a small, small part of the bacteria or virus that these vaccines are protecting against,” she said.

Babies begin dealing with bacteria and other microbes as soon as they pass through the birth canal. By the end of the first week, the baby’s skin, nose, throat and intestines are covered with tens of thousands of different bacteria.

“All of these bacteria, they are each going to have anywhere from 2,000 to 6,000 little proteins that our body could respond to if they do cause infections,” she said.

By comparison, vaccines have only a few of these stimulating proteins, she said.

“Just enough to help our bodies make an immune response so that we’ll have immune memory -- then we’ll be able to recognize a bacteria or virus when we are actually exposed and make antibodies for protection right away.”

It seems as if children are getting more vaccines than before. Doesn’t that overwhelm their immune system?

Experts say that while children receive more vaccines now, the vaccines are more precise than before because of better scientific understanding of how to train the immune system to defend children against diseases.

Thirty years ago, children received vaccines that protected against eight diseases: measles, mumps, rubella, diphtheria, tetanus, pertussis, Haemophilus influenzae type b and polio. The total number of bacterial and viral proteins contained in earlier versions of these vaccines was a little more than 3,000.

Today, young children receive vaccines that protect against 14 diseases: the eight earlier ones plus hepatitis A, hepatitis B, rotavirus, influenza, chickenpox and pneumococcal disease. But the total number of bacterial and viral components in these vaccines is only about 150.

When the vaccine for pertussis, or whooping cough, was developed, for example, it had about 3,000 such components, Feemster said. Now the vaccine contains three to five proteins.

Doesn’t it hurt the kids to get so many shots at once?

Studies have shown that it is just as stressful for babies to receive one shot as it is to receive more than one shot.

“Receiving two shots every month could be even more stressful than getting four shots at once,” Feemster said. Splitting each set of immunizations into two visits just doubles the stress in a child’s life.

Some parents say they would prefer to space out their children’s shots. Why is that bad?

“If infants don’t get vaccinated as recommended, it really increases the time they could be at risk of getting vaccine-preventable diseases,” Feemster said.

If a 2-month-old doesn’t get a recommended vaccine dose to protect against pertussis, the baby could get this highly contagious disease and become severely ill, she said. Up to 80 percent of babies with whooping cough end up in the hospital, and about 1 in 100 infants die.

Whooping cough makes children cough uncontrollably. The cough is often so hard and so persistent that children make a pitiful “whooping” sound.

“We’ve seen a lot of whooping cough,” said Feemster, who attributed the cases in part to unvaccinated children. When children are not up to date on their vaccines, it not only increases the risk of disease for them, but also increases the risk that it will spread to other vulnerable people, she said. “It’s a community issue in many ways.”

How do we know that the recommended schedule is the best schedule?

The federal government has a committee that reviews all available data on vaccine effectiveness and safety, and it updates the recommendations every year. It’s called the Advisory Committee on Immunization Practices, or ACIP. Its members include experts in pediatrics, epidemiology, immunology, public health, ethics as well as a member of the public to represent patients and families who would receive vaccines. Several of its liaison groups include professional organizations, including the American Academy of Family Physicians  and the American Academy of Pediatrics.

“This is a schedule that really has been vetted and developed after consideration of the best way to make sure to protect babies when they are at highest risk for serious disease and the way to do it safely,” Feemster said.

The panel issues guidelines that are widely followed, including recommendations for childhood vaccines that form the basis for vaccination requirements set by public schools. The recommendations include when a vaccine should be given, the number of doses needed, the amount of time between doses, and precautions and possible allergic reactions.

The effectiveness of the vaccine schedule is tested extensively to ensure that the vaccines in the combination don’t interfere with one another and can be easily handled by the infant and the child’s immune system. No new immunization is added to the schedule until it has been evaluated both alone and when given with the other current immunizations.

Why do so many people think vaccines are dangerous?

About 20 years ago, an article in a respected medical journal claimed to show a link between vaccines and autism. The study was later found to be a fraud, but it planted seeds of doubt about vaccines at a time when autism diagnoses were increasing. Since then, many studies from around the world have shown conclusively that there is no link between vaccines and autism, and the apparent increase in autism is largely due to a broader definition of the condition and better diagnosis.

Every major scientific and medical organization has evaluated the evidence and concluded that vaccines only very rarely cause side effects and that the benefit of protecting children from disease massively outweighs any risk. But some prominent figures, including President Trump, have spread misinformation about vaccines, and the myth that they are dangerous persists.

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