Tag: contagious

Which Vaccines Don’t Prevent the Spread of a Disease?

As most folks know, Dr. Bob Sears has been put on probation by the California Medical Board.

Most vaccines don't prevent the spread of diseases?
Most vaccines don’t prevent the spread of disease???

Surprisingly, that hasn’t kept him from posting dangerous misinformation about vaccines, including his latest idea that “most vaccines don’t prevent the spread of a disease.”

Which Vaccines Don’t Prevent the Spread of a Disease?

If vaccines don’t prevent the spread of disease, then how did we eradicate, eliminate, and control so many diseases?

Dr. Bob Sears actually reassured parents that measles wasn't deadly in developed countries, neglecting to mention the dozens of people who have died in outbreaks in Europe - another well-nourished population with lower vaccination rates than the U.S.
At least seven people have died in Italy with measles over the last few years. That’s not so good for Italy.

When was the last time you saw someone with small pox, rubella, diphtheria, or polio, for example?

It is true that vaccines don’t prevent the spread of some infections though.

There is tetanus, for example, but guess what?

Tetanus isn’t contagious.

Any others?

Well, unlike most other vaccines, the meningococcal B vaccines are not thought to decrease nasal carriage of the meningococcal B bacteria. So if you are vaccinated and an asymptomatic carrier of the bacteria, you could theoretically spread it to someone else, as could someone who is unvaccinated.

Still, the MenB vaccines can protect you from getting actual meningococcal B disease, and if you don’t have meningococcemia or meningococcal meningitis, you won’t expose and spread it to someone else. That’s why the MenB vaccines are especially useful in outbreak situations.

Any others? After all, Dr. Bob did say that “most vaccines don’t prevent the spread of a disease.”

Vaccines That Don’t Prevent the Spread of a Disease

There are a few other examples of vaccines that don’t prevent the spread of a disease.

“I also warn them not to share their fears with their neighbors, because if too many people avoid the MMR, we’ll likely see the diseases increase significantly.”

Dr. Bob Sears in The Vaccine Book

Of course, any vaccine that is delayed or skipped won’t work to prevent the spread of a disease.

Just like they are seeing measles outbreaks and deaths now, because of low vaccination rates, in Ukraine there were 17,387 cases of diphtheria and 646 deaths from 1992 to 1997. Also high, were cases of measles (over 23,000 cases in 1993) and pertussis (almost 7,000 cases in 1993).

And because of waning immunity, vaccines don’t do as good a job of preventing the spread of pertussis and mumps as we would like. Still, that’s only when the vaccines don’t work, and even then, as Dr. Bob says, they do work to reduce the severity of symptoms.  During recent mumps outbreaks, the rates of complications are far below historical levels. The same is true for pertussis.

Have you ever seen or heard an unvaccinated child with pertussis? It is truly heartbreaking, especially when you realize how easily it could be prevented.

We typically see the same thing with flu. Even when the flu vaccine isn’t a good match or isn’t as effective as we would like, it still has a lot of benefits, including reducing your risk of dying.

“IPV induces very low levels of immunity in the intestine. As a result, when a person immunized with IPV is infected with wild poliovirus, the virus can still multiply inside the intestines and be shed in the faeces, risking continued circulation.”

Inactivated poliovirus vaccine

Does the fact that IPV, the inactivated polio vaccine, can sometimes lead to infections and shedding mean that it doesn’t prevent infections?

Of course not!

“IPV triggers an excellent protective immune response in most people.”

Inactivated poliovirus vaccine

Most people vaccinated with IPV will be immune, won’t get wild polio, and so won’t be able to get anyone else sick.

Vaccines reduce disease by direct protection of vaccinees and by indirect protection of nonimmune persons. Indirect protection depends on a reduction in infection transmission, and hence on protection (immunity) against infection, not just against disease. If a vaccine were to protect only against disease, and not at all against infection, then it would have no influence on infection transmission in the community and there would be no indirect protection (vaccination of one person would have no influence on any others in the community). It would be possible to reduce disease with such a vaccine but not to eradicate the infection.

Plotkin’s Vaccines

But because IPV doesn’t provide indirect protection, we still use OPV in parts of the world where polio is more of a problem.

Vaccines work. Even the few that don’t prevent the spread of infections, still help to reduce disease.

What’s the Difference Between Infections and Disease?

Wait, is there a difference between infection and disease?

Yes there is, something that Dr. Bob, who actually wrote a book about vaccines, seems to have overlooked.

An infection is simply the presence of a virus, bacteria, or other organism in your body.

A disease, on the other hand, is a virus or bacteria in your body causing signs and symptoms.

All vaccines work to prevent disease, or at least they do when you actually get vaccinated.

A very few don’t prevent infections and the spread of infections, but that is not a good reason to skip or delay your child’s vaccines. In fact, it is one of the reasons why it is important to have high vaccination rates! Even natural infections don’t always keep you from becoming asymptomatic carriers that can infected others. Many people who have natural typhoid (remember Typhoid Mary?) and hepatitis B infections go on to become chronic carriers without any symptoms, but still able to infect others.

If you understand that a few vaccines don’t prevent the spread of infections, then you should understand that you can’t hide in the herd and expect to be protected, even though most folks around you are vaccinated.

What to Know About Vaccines and the Spread of Disease

Despite what Dr. Bob says, almost all vaccines work to prevent the spread of disease and infections, at least they do when you get your kids vaccinated.

More on Vaccines and the Spread of Disease

What to Do If Your Child Is Exposed to Pertussis

Although things are much better than they were in the pre-vaccine era, we still have pertussis outbreaks in the United States.

How does that work?

Waning immunity and folks who are unvaccinated.

How Contagious is Pertussis?

Pertussis is very contagious, but not quite as contagious as other vaccine-preventable diseases, such as measles.

That’s why the focus on controlling pertussis outbreaks is usually looking at close contacts – those who were within about 3 feet for at least 10 hours a week or who had direct face-to-face contact with the person when they were contagious.

Have you gotten a letter from your child's school about pertussis yet?
Have you gotten a letter from your child’s school about pertussis yet?

So when you get a letter about a possible case of pertussis in your child’s school, it may be a a general warning and not that your child is at risk.

How do you get pertussis?

“Persons with pertussis are infectious from the beginning of the catarrhal stage through the third week after the onset of paroxysms or until 5 days after the start of effective antimicrobial treatment.”

Manual for the Surveillance of Vaccine-Preventable Diseases

Spread by respiratory droplets (coughing and sneezing), pertussis symptoms usually start about 5 to 10 days after being exposed to someone else who is in the early stage of their pertussis infection.

While pertussis symptoms can linger for up to 10 weeks, someone who has pertussis is most contagious during the first 2 or 3 weeks of symptoms.

Is Your Child Protected Against Pertussis?

Two pertussis vaccines, DTaP and Tdap, help protect us against pertussis.

In the Unites States, they are routinely given as a primary series (DTaP) at 2, 4, and 6, and 15 to 18 months, with a booster dose at age 4 years. And then a booster of Tdap at age 11 to 12 years. Later, Tdap is given again during each pregnancy, between 27 and 36 weeks gestation. Adults who have never had a dose of Tdap should get caught up, especially if they will be around a baby.

Protection from the pertussis vaccines wanes or wears off, so even fully vaccinated children and adults can still get pertussis. Of course, you are much more likely to get pertussis if you are unvaccinated and you will likely have more severe illness if you are unvaccinated.

Postexposure Antimicrobial Prophylaxis for Pertussis

Fortunately, as with meningitis was caused by Neisseria meningitidis and Haemophilus influenzae type b (Hib), taking antibiotics after being exposed to someone with pertussis can help prevent you from getting sick.

There are only specific situations for which this type of postexposure antimicrobial prophylaxis is recommended though, so for example, you wouldn’t usually give everyone in a school antibiotics because a few kids had pertussis.

Why not give antibiotics to everyone who might have been exposed to someone with pertussis?

“…there are no data to indicate that widespread use of PEP among contacts effectively controls or limits the scope of pertussis outbreaks.”

Postexposure Antimicrobial Prophylaxis

In addition to the fact that it likely wouldn’t stop our pertussis outbreaks, overuse of antibiotics can have consequences.

Situations in which postexposure antibiotics (azithromycin, clarithromycin, and erythromycin, or Bactrim) likely would be a good idea include:

  • household contacts of a known pertussis case
  • to help control an outbreak in a limited closed setting, like a daycare
  • contacts of a pertussis cases who are at high risk for severe pertussis, including pregnant women, infants, especially infants less than 4 months old, and people with chronic medical problems
  • contacts of a pertussis cases who are also contacts of someone who is at high risk for severe pertussis

What if you were exposed to someone with pertussis and have already gotten sick?

If your child was exposed to pertussis and is now coughing, then in addition to antibiotics, pertussis PCR testing and/or culture will also likely be done to confirm that they have pertussis. And remember that their contacts might need postexposure antibiotics.

Kids who have been exposed to pertussis and who have been coughing for more than 3 weeks won’t need antibiotics or testing, as it is too late for the antibiotics to be helpful and likely too late for testing to be accurate. Fortunately, after 3 weeks, they should no longer be contagious.

What to Do If Your Unvaccinated Child Is Exposed to Pertussis

Unvaccinated kids who are exposed to pertussis should follow the postexposure antimicrobial prophylaxis guidelines.

They should also get caught up on their immunizations, including DTaP if they are between 2 months and 6 years, or Tdap if they are older.

What to Do If Your Vaccinated Child Is Exposed to Pertussis

Since protection from the pertussis vaccines wanes, even kids who are fully vaccinated should follow the postexposure antimicrobial prophylaxis guidelines if they are exposed to pertussis.

Then why get vaccinated?

Again, being vaccinated, your child will be much less likely to get pertussis than someone who is unvaccinated. Even though the pertussis vaccine isn’t perfect, it has been shown that children who had never received any doses of DTaP (unvaccinated children) faced odds of having pertussis at least eight times higher than children who received all five doses.

What to Know About Getting Exposed to Pertussis

Talk to your pediatrician if your child gets exposed to pertussis to make sure he doesn’t need post-exposure prophylaxis to keep him from getting sick, even if you think he is up-to-date on his vaccines.

More on Getting Exposed to Pertussis

How Can the Unvaccinated Spread Diseases They Don’t Have?

Folks who are intentionally unvaccinated often have a hard time understanding why the rest of us might be a little leery of being around them.

That’s especially true if we have a new baby in the house, younger kids who aren’t fully vaccinated and protected, or anyone with a chronic medical condition who can’t be vaccinated.

Why? Of course, it is because we don’t want them to catch measles, pertussis, or other vaccine-preventable diseases.

“How can you spread a disease that you don’t even have?”

It’s true, you can’t spread a disease that you don’t have.

But infectious diseases don’t magically appear inside our bodies – we catch them from other people. And if you have skipped or delayed a vaccine, then you have a much higher chance of getting a vaccine-preventable disease than someone who is vaccinated and protected.

So, just avoid other people when you are sick, right?

“…the increased risk of disease in the pediatric population, in part because of increasing rates of vaccine refusal and in some circumstances more rapid loss of immunity, increases potential exposure of immunodeficient children.”

Medical Advisory Committee of the Immune Deficiency Foundation

That works great in theory, but since you are often contagious before you show signs and symptoms and know that you are sick, you can very easily spread a disease that you don’t even know that you have.

An infant hospitalized during a measles outbreak in the Philippines in which 110 people died.
Children with measles are contagious 4 days before through 4 days after their rash appears, but you often don’t recognize that it is measles until they get the rash! Photo by Jim Goodson, M.P.H.

There’s the trouble:

  1. being unvaccinated, you or your child are at higher risk to get sick
  2. when you get sick, you can be contagious several days before you have obvious symptoms
  3. you can spread the disease to others before you ever know that you are sick, or at least before you know that you have a vaccine preventable disease

This makes intentionally unvaccinated folks a risk to those who are too young to be vaccinated, are too young to be fully vaccinated, have a true medical exemption to getting vaccinated, or when their vaccine simply didn’t work.

measles-santa-clara-county
Folks with measles often expose a lot of other people because they don’t yet know that they have measles and aren’t showing signs and symptoms yet.

In fact, this is how most outbreaks start. Tragically, kids too young to be vaccinated get caught up in these outbreaks.

Keep in mind that these parents didn’t have a choice about getting them protected yet. Someone who decided to skip their own vaccines made that choice for them.

And remember that while you can’t spread a disease that you don’t even have, you can certainly spread a disease that you don’t realize that you have.

What to Know About The Unvaccinated Spreading Disease

If you aren’t going to get vaccinated or vaccinate your kids, understand the risks and responsibilities, so that you don’t spread a vaccine-preventable diseases to others that you might not even know that you have yet.

More on the Unvaccinated Spreading Disease

What to Do If Your Child Is Exposed to the Flu

During a bad flu season, especially when effectiveness of the flu vaccine is less than ideal, parents want to know how to protect their kids from the flu.

Protecting Kids from the Flu

Cover your coughs and sneezes so you don't spread the flu virus to other people.
Covering your coughs and sneezes might help prevent the spread of the flu virus to other people.

Of course,  the best way to protect kids from the flu and serious complications of the flu is to get a flu vaccine each year.

Still, the flu vaccine isn’t perfect.

So, what else can you do?

Like other respiratory diseases that are mainly spread by coughing and sneezing, you can help reduce the risk that your kids will get sick by:

  • as much as possible and practical, keeping your kids away from other people, especially those who are obviously sick
  • encouraging your kids and others to properly cover their coughs and sneezes
  • teaching your kids to wash their hands properly
  • encouraging your kids to not touch their eyes, nose, or mouth, or to bite their nails or put things in their mouth, like their pencil or pen
  • cleaning and disinfecting surfaces that your child will likely touch
  • encouraging others to stay home from school or work when they have the flu until they are fever free for at least 24 hours, although they might be contagious for even longer

While these techniques might not work, they are certainly better than doing nothing and simply letting your kids catch the flu.

What to Do If Your Child Is Exposed to the Flu

If your kids do anything outside the home, even if they don’t go to daycare or school, there might come a time during a long flu season when they get exposed to someone with the flu.

What do you do?

“Prevention (prophylaxis) is a term used when someone who does not have flu symptoms is given Tamiflu to help stop them from getting the flu because they are exposed to or come into close contact with someone (for example live with or take care of someone) who has the flu.”

FDA on Tamiflu: Consumer Questions and Answers

In addition to watching for classic flu symptoms to develop over the next one to four days, if your child is unvaccinated or it is a year during which the flu vaccine is not very effective, if your child is in a high risk group for severe complications from the flu (under age two to five years or any age with chronic medical problems), then you might ask your pediatrician about:

  • a once a day dose of Tamiflu (Oseltamivir), which is recommended as a preventative in infants as young as three months old
  • a once a day dose of Relenza (Zanamivir), which is recommended as a preventative in children as young as five years old, unless they have respiratory problems, like asthma

But that doesn’t mean that everyone should take these flu medicines every time they are exposed to someone with the flu. If these medicines are overused, flu viruses will develop resistance and they won’t work, just like happened to some of the older anti-viral flu medicines, amantadine and rimantadine.

Still, if your child with diabetes, uncontrolled asthma, muscular dystrophy, or healthy four month old is closely exposed to someone with the flu, then taking Tamiflu to prevent a potentially severe case of the flu is likely a good idea.

What to Do If Your Child Gets the Flu

And if your child gets the flu?

Believe it or not, most healthy school age kids with the flu don’t need to be seen by their pediatrician.

“When treatment is started within two days of becoming sick with flu symptoms, antiviral drugs can lessen symptoms and shorten the time you are sick by about one day. They may reduce the risk of complications such as ear infections in children, and pneumonia and hospitalizations in adults. For people at high risk of serious flu complications, early treatment with an antiviral drug can mean the difference between having milder illness instead of more severe illness that might require a hospital stay.”

CDC on What You Should Know About Flu Antiviral Drugs

You should see your pediatrician or other health care provider at the first sign of flu symptoms if they are at high risk for serious complications of the flu and they might benefit from Tamiflu, which includes those under two to five years old and children with any chronic medical problems.

And of course, seek medical attention if your child with the flu is showing signs of a severe case of the flu, such as trouble breathing, dehydration, or being inconsolable, etc.

You should also seek medical attention if your child with the flu was getting better, but then starts to get worse again, with a return of fever, worsening cough, or severe headache, etc.

When in doubt, call your pediatrician!

What to Know About Protecting Kids from the Flu

In addition to avoiding people who are sick with the flu, see your pediatrician as soon as possible if your younger, high risk child is gets sick after being exposed to someone with the flu.

More on Protecting Kids from the Flu