Vaccines

You shouldn’t get a vaccine if you are sick

We can’t tell you how many times we’ve been asked about this in the office. Most people understand why it’s important to get vaccinated, but there are a lot of misunderstandings about when or how to get vaccines. One of these misunderstandings is that vaccines don’t work, or are even dangerous, if you are ill.

First, it is worth reviewing how vaccines work. In a nutshell, vaccines contain substances that mimic the germs that can cause certain illnesses. While the substances in vaccines cannot cause actual illness, they cause the body’s immune system to react in such a way as to create antibodies that can later defeat the actual illness.

As with many of the myths in this book, there is a kernel of truth in the myth that has run amok. In this case, there is some evidence that vaccines could cause changes in how your body reacts to particular things, like the TB skin test. This led some to theorize that vaccines would lead to increased illnesses in the period after they were given. Some parents worry that if the body is busy responding to the vaccine, it will not be able to respond to other things that might make you sick. Fortunately, that’s not so. A study of almost 500 children in Germany found that infants in the first three months of life who received vaccines had fewer, not more, illnesses from germs both related and not related to the vaccines. Another study of children in Alaska receiving the DTP (diphtheria, tetanus, pertussis) vaccine found no relationship between getting vaccines and increased risks of other infections.

Another strain of this myth centers on the idea that vaccines won’t work as well if you are sick. That’s not true, either. A study in Canada found that having an upper respiratory tract infection in the month before a vaccination, during a vaccination, or up to a week after a vaccination had no effect on the body’s response to the vaccine. A different study in Haiti a decade earlier also found that neither malnutrition nor acute infections affected the vaccine response. One more study from the mid-1990s in Atlanta found that the success of the vaccine in achieving the proper response was nearly identical between well children and those with upper respiratory infections, mild fevers, ear infections, diarrhea, and mild illnesses. Nor were there any more adverse events in the ill children than in the well children. Vaccines work just as well when you are sick with most illnesses. This myth is of concern because parents who delay getting vaccines for their children because of a mild illness may not return promptly to catch up on the shots. And children who fall behind, or do not receive their vaccines, are at increased risk to get vaccine-preventable illnesses. We need to use every opportunity to give vaccines in order to optimally protect babies and children from these diseases.

The big groups that make recommendations on vaccines, like the Centers for Disease Control and the American Academy of Pediatrics, recommend that people who are severely, and sometimes moderately, ill delay vaccines until they are better. Your doctor can help you in these kinds of decisions. But there’s nothing to fear from getting vaccines when your child is mildly ill. They don’t increase the risk to your child (and may even reduce it) and the vaccines will work just fine.

Getting the flu vaccine is more important for adults than children

As pediatricians, this one hits closer to home than some of the other myths. It’s hard enough convincing people that the flu shot is important for the elderly. It’s even harder to convince parents that it’s important for their children.

Look, we acknowledge how hard it is to get your children vaccinated. They are getting so many shots already, and you don’t want to add one more. It can be hard to get an appointment, especially during flu season, when everyone else is trying to get their children the shot. There are often shortages, making it time-consuming even to know whether it is worth going for the shot. And then, even if everything works out and you can fit them in, you need to take off work or rearrange appointments or have your child miss school. Is the flu shot really that important?

People also question the value of the flu shot for children because of a general perception that children aren’t really at risk from the flu. You may have read the chapter about how influenza kills many people each year, but those people are mostly the elderly, right?

The short answer to that question used to be yes. Until recently, more than 90 percent of deaths that occurred from flu in the United States were in people sixty-five years old or older. Nonetheless, the regular flu still kills and hospitalizes children and babies every year. With the introduction of H1N1, the picture for children becomes more of a concern. Here are some facts from the outbreak in 2009–2010:

The cumulative hospitalization rate for flu for children up to four years of age was 8.3 per 10,000. This was two to three times higher than the rates for adults, and still more than twice the hospitalization rate for people over sixty-five.

There were 279 lab-confirmed flu deaths, which was four times the average of the previous five years.

Of those 279 deaths, 226 were from the H1N1 strain.

No matter how you want to look at it, H1N1 has changed the game. Kids are more at risk than ever. They are more likely to be hospitalized, and more likely to die. So if you want to protect your kids, you need to get them the shot.

So far, this argument ignores the larger truth about vaccines. Sometimes we don’t get vaccinated to protect ourselves. We often get vaccinated to protect others. It’s a societal good.

The reason we vaccinate health care workers is to protect patients just as much as the clinicians. Sometimes, the reason we vaccinate older children is to protect younger children in the house. And we vaccinate the general population in part to protect the elderly. When we come in contact with older people vaccination makes it much less likely we will pass the disease on to them. Many children have regular contact with their grandparents. If children are ill, even if they are not at risk themselves, they can be a risk to the elderly. It’s not an argument used often, but that makes it no less true. It’s important to vaccinate children not only to protect them, but also to protect those that they love.

Too many vaccines will weaken your immune system

Shots are no fun. And, believe us, doctors and nurses don’t like giving them any more than you like getting them. People are always looking for reasons not to get shots. This myth is one of the most commonly used excuses. Parents worry about the number of shots their babies are supposed to get and will often develop elaborate plans to spread the shots out over a much longer period of time so that the immune system does not need to respond to too many shots at once.

Let’s start by recognizing that the human body has an enormous capacity to respond to potential threats. You are constantly exposed to foreign substances that stimulate your immune system. In a manuscript specifically designed to answer this question in the journal Pediatrics, Dr. Paul Offit and colleagues estimated that infants have the capacity to respond to about 10,000 vaccines at any one time. No vaccine could “use up” the immune system. In fact, estimates showed that if a child received eleven vaccines at one time, that might occupy about 0.1 percent of the immune system. You’d never notice that.

Moreover, this argument against vaccines assumes that the cells being occupied or destroyed in the vaccine response process are not replaced. You body is constantly making new cells, though, so this never occurs.

Another point, often overlooked, is that it is not the number of vaccines, or even the number of shots, that matters. It’s the number of antigens in those vaccines. An antigen is a molecule that the immune system recognizes. The immune system decides whether any molecules it comes in contact with belong to itself or whether they should be treated as foreign intruders. Vaccines are specifically designed to show the immune system an antigen that belongs to a particular disease so that the immune system will be armed and equipped to fight against that disease if it sees it again. Advances in technology have helped scientists create vaccines that contain fewer and fewer antigens and yet achieve a good response from your immune system. Back in the day, a single smallpox vaccine had over 200 different proteins in it. In the 1980s, the seven vaccines routinely given to children contained more than 2,000 antigens. Now the eleven vaccines in the currently recommended schedule have only about 125 antigens in all. Even though it seems like a lot of shots, the immune system has to do far less work to respond to the current set of antigens than children’s immune systems had had to do the past thirty years.

Don’t take our word for it. Research has shown that giving vaccines alone or in combination does not affect their ability to achieve a response. A trial comparing the effectiveness of the MMR (measles, mumps, rubella) and chickenpox vaccines given together and alone showed no difference in their effectiveness. The immune system responds how it should whether the shots are given separately or at the same time. Another study compared the effect of giving MMR, DTP, and polio boosters at the same time to giving the vaccines individually, one after the other. The vaccines were just as effective when they were given at the same time as when they were given individually. The immune system responded just as well when the shots were combined together. The same result was seen when looking at adding hepatitis B vaccine to other vaccines in infants. Your body can easily handle the load.

If you remain concerned that giving a vaccine weakens the immune system, studies show us this is not the case. Remember that study of almost 500 children in Germany? They had fewer illnesses after the vaccines, not more. The babies’ immune systems were working fine! In fact, the immune systems in the children getting the shots may have even been working better. There was also that study of children in Alaska receiving the DTP vaccine where children who got that vaccine did not get more infections from other sources.

Some have theorized that giving more vaccines over time has led to an increase in conditions like autism. We addressed that myth in our first book, Don’t Swallow Your Gum!, and two years later, there is still no good evidence to support that theory. One huge study after another concludes that there is no link between vaccines and autism. Those ideas also ignore the truths revealed here—that the number of antigens children are exposed to has been going down, not up.

We don’t want to poke your children any more than you do. But they really do benefit from those vaccines.