Posted tagged ‘vaccination’

Pertussis is making a comeback – what’s the best protection?

June 12, 2019

The Pediatric Insider

© 2019 Roy Benaroch, MD

Pertussis is also known as “whooping cough”, or sometimes “the 100 day cough”, or sometimes “DAMMIT WHY CAN’T I STOP COUGHING?!”. It is truly miserable. In adults and teens, three months of coughing – and I mean serious, loud, hard coughing, sometimes until you break a rib, vomit, or pass out – is not fun. Young babies, instead of coughing their little heads off, sometimes just stop breathing.

Unfortunately, it’s making a comeback. Both national statistics and our experience at my offices are showing increasing numbers of pertussis cases. Pertussis had become very uncommon with widespread vaccination by the 1980s. Why is it back?

(Aside: about 25 years ago, in my very first month of training as a pediatrician, I was taking care of a newborn in the emergency department who stopped breathing. Completely. Just stopped. Turned blue and floppy. I was terrified, but kept my cool and performed mouth-to-mouth resuscitation. The baby did fine. Later, my attending told me to never use my mouth on a baby – there was resuscitation equipment literally hanging on the wall behind me that I didn’t think to use. Oops. Later, I found out the baby had pertussis.)

The first pertussis vaccine was developed in the 1930s, and in the 1940s it was combined with tetanus and diphtheria vaccines to create the “DTP” vaccine. This was very effective at preventing pertussis, but it was quite “reactogenic”. DTP commonly causing fevers and sometimes febrile seizures (which, by themselves, are harmless – but really scary.) There were cases of encephalitis and dramatic developmental regression seen, too, though it’s become clear since then that these were cases of the genetic condition Dravet Syndrome, which unfortunately starts showing symptoms around the time DTP was given. The quest was on for a pertussis vaccine that caused fewer fevers, and a newer, more purified “acellular” DTaP was developed.

After extensive studies showed that the DTaP was effective and caused fewer fevers, the acellular vaccine replaced the older, “whole cell” vaccine in the US and many other developed countries in the 1990s. And, at least at first, things seemed to go well. Pertussis cases remained low.

But we’ve seen a steady increase in cases over the last 10-15 years. Part of that could be ascertainment bias – there are newer, better, and faster tests for pertussis that have come into wider use, and doctors think about testing more kids for pertussis now that’s clear there are more cases. That doesn’t explain all of the increase.

A study published this week in Pediatrics has helped clarify what’s going on. About a half million children managed at the huge Kaiser Permanente system in Northern California were studied, looking at their pertussis vaccine status and the rates of proven cases of pertussis in the group. Almost 750 cases of pertussis were documented in these children from 2006-2017, revealing some important conclusions:

  • Pertussis risk, overall, was 13 times higher in unvaccinated versus fully-vaccinated children. The vaccine is protective.
  • Still, 80% of the cases occurred in children who had received the full set of doses. Pertussis immunity dropped off over time – and the longer since the most-recent dose, the more at-risk a vaccinated child became.

So what should we do?

First: widespread, continued universal DTaP vaccinations in infancy and Tdap boosters for preadolescents is still a good idea. It is far better than not vaccinating. The Kaiser data clearly shows vaccinated individuals are at lower risk. Since one of the highest risk groups for severe disease is newborns, vaccinating pregnant women is a key strategy. Though maternal pertussis immunity after Tdap doesn’t last long, it does last long enough to transfer protective antibody to the unborn baby, providing crucial protection during the first few months of life.

But we clearly need a better vaccine and other strategies to provide better, more-lasting protection. Alternatives are being studied, including a nasal-spray pertussis booster and new, adjuvanted vaccines that can hopefully provide more-lasting protection safely. New vaccines take many years to study, so don’t expect anything on the market soon.

In the meantime, we need to do the best we can. Make sure you and your children are fully vaccinated against pertussis, and follow the recommendations for all vaccines. We need to be a better job developing better tools, but in the meantime we could be doing a better job using the tools we’ve already got.

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Chicken pox vaccine prevents shingles, too

June 10, 2019

The Pediatric Insider

© 2019 Roy Benaroch, MD

A study published today in Pediatrics confirms good news about routine chicken pox vaccination in children: it also prevents shingles. Smaller studies had seemed to show this was likely, and this huge new study of over 6 million children nails it down. And: the benefit seems to apply to all of our children, even those unable to be vaccinated.

A little background: chicken pox and shingles are both caused by the same virus, named “Varicella Zoster Virus”, or VZV. When people first catch this very contagious illness, they get a painful and itchy rash accompanied by fever – that’s chicken pox. It’s a miserable experience – I remember when I had it, a summer long ago – that can also lead to complications like pneumonia, life threatening skin infections, and encephalitis. Even when you’ve recovered from chicken pox, the sneaky devil-virus hides in your nerve cells, waiting for an opportunity to swing back into action. And that recurrence of symptoms is what’s known as shingles, or “zoster” – a very uncomfortable rash that can leave lasting pain that can very difficult to control. Zoster especially likes to pop back up when you’re already sick or having other health problems, just to give you an extra poke in the eye.

“Remember me?” VZV says. “Have some pain!”

A vaccine to prevent VZV infections was developed in Japan in the 1970’s. It was specifically targeted at first for children undergoing chemo for leukemia, because so many of them were dying of overwhelming VZV infections (in people with suppressed immune systems, primary or recurrent VZV infections can be devastating.) The vaccine was very successful in saving lives and preventing misery in these children, which led to more-widespread testing in healthy kids and the adoption of widespread chicken pox vaccinations in the 1990’s. Later, it was shown that two doses worked better than one, and the current guidelines in the US recommend two doses be given routinely to all children starting at 12 months of life. This protects not only the children who get the vaccine, but their families and their communities, including people who can’t be vaccinated and children and adults on chemo or other medicines that suppress their immune systems (By the way: there are a lot of these people around. Including some of your friends and their children. Immune-suppressing “biologic” agents are now used routinely to improve the lives of people with psoriasis, Crohn, rheumatoid arthritis, and many other diseases. You’ve got friends, neighbors, and coworkers on these medicines. You can help protect them.)

A fair question to ask: do routine chicken pox vaccines also prevent VZV from recurring – that is, do they prevent shingles? Those studies in immunocompromised children showed it definitely did, but we needed years of data to prove that it was also effective in the broader population, because shingles may occur many years after chicken pox. And now, we’ve got solid data.

This study was done at six sites in the US, mostly in California, following the medical records of 6,372,067 children for 12 years. The results are impressive. First: rates of zoster/shingles dropped dramatically in the whole population, by about 50%, over the 12 years. Even in children who weren’t vaccinated, zoster is boing prevented by the use of this vaccine. But the effect was much larger children who did get the vaccine, and larger still among children who got the full course of two doses rather than one.

Vaccine science is always evolving, and important studies continue – there is always more to learn. All of the good evidence so far had shown that this vaccine was preventing both chicken pox and shingles, and this long-term, huge study adds to the evidence. Make sure your children and your family are up to date on their vaccines, including this chicken pox vaccine, to best protect yourself and your community. We’re all in this together, folks. Do the right thing. Vaccinate.

 

It’s time to rethink pertussis prevention

February 8, 2016

The Pediatric Insider

© 2016 Roy Benaroch, MD

A large, sobering study published in the March, 2016 edition of Pediatrics illustrates just how far we still need to go to effectively control pertussis.

Pertussis, also known as ‘whooping cough’, is a serious illness. Older children and adults get to enjoy a horrible cough for about three months—a cough that sometimes makes people vomit, break ribs, or pass out. Seriously. You haven’t seen a “bad cough” until you’ve seen the cough of pertussis. Worse: in little babies pertussis can cause breathing problems, seizures, and death. Though its caused by a bacteria, antibiotics (unless given very early) are ineffective at reducing the length or severity of pertussis. Prevention, in this case, is worth far more than a pound of cure.

Up until the mid-1990s, infants and children routinely received the whole-cell DTP vaccine (DTP = diphtheria, tetanus, pertussis.) It worked at preventing all three of these diseases, but had a relatively high rate of side effects, mostly fevers. Many of the suspected more-serious side effects (like encephalopathy and seizures) are now known to have been caused by genetic conditions, not the vaccine, but nonetheless parents and doctors alike welcomed a newer vaccine, the acellular DTaP. This newer vaccine, which replaced DTP in the United States by around 1998, caused fewer fevers, and was thought to cause fewer serious reactions, too.

The problem is that it just doesn’t work as well. And as the first generation of infants to get an all-DTaP series starts to go through adolescence, we’re starting to see the unintended consequence of that vaccine change.

In the current study, researchers used a huge database of information from the Kaiser Permanente system of Northern California. We’re talking solid, big-data research, here, the kind of study that requires consistent and reliable data across a huge set of patients. In this case, about 3.5 million patients across 55 medical clinics and 20 hospitals, using centralized labs and an integrated medical records system. If health things happen to this population, Kaiser knows it.

In 2010 and again in 2014, California experienced large epidemics of pertussis. A total of 1207 cases were among Kaiser teenagers, all with complete records of their pertussis vaccination status. And the results aren’t anything to be happy about. In the first year after an adolescent pertussis (Tdap) booster, the vaccine was about 70% effective in protecting against pertussis. Not great, but not terrible, either – until you look a few days down the road. The vaccine effectiveness drops off dramatically, year after year, down to only about 9% by four years after receipt of the vaccine.

Why does Tdap seem to provide such poor protection—much worse than was seen in the original licensing studies? It’s a generational change, and it goes back to the shift from DTP to DTaP in the mid-1990s. By now, these teens in California are old enough to have received DTaP, not DTP, as infants. The authors looked at the specific ages of pertussis cases during the 2010 and 2014 outbreaks, and the trends support the conclusion that teens who received DTP as infants get good, lasting protection from Tdap; teens who got DTaP do not.

Now what? Clearly, we need a more-effective vaccine, perhaps even resuming the use of whole-cell pertussis vaccine, at least for the earlier doses. But in the meantime, we have to do the best we can with what we have. Vaccinating pregnant women with Tdap does effectively prevent pertussis in their babies, especially when they’re the youngest and most-vulnerable. And adults (who got DTP as children) should get Tdap boosters too, to protect the children around them. Another idea (floated by the study authors) is to use Tdap in teens not as a routine booster, but as a strategy to control local outbreaks, taking advantage of the higher effectiveness seen for the first year after vaccination.

I don’t have the answers. I’m not happy to see studies like these, but examining and re-examining vaccine safety and effectiveness is something we need to continue doing, with an open mind, relying on solid evidence. Bottom line: with pertussis, we need to do better.

Whooping crane

A few surprising vaccine myths – Betcha didn’t know!

February 23, 2015

The Pediatric Insider

© 2015 Roy Benaroch, MD

Myth 1: Vaccines work by preventing disease in individuals who are vaccinated.

Nope, that’s not actually true—it’s quite wrong, but in a subtle way. And a misunderstanding of this concept, I think, has led to a lot of mischief. If people understood how vaccines really work, how they can best protect us from disease, it might help overcome some skepticism.

Vaccines do indeed prevent diseases in individuals, but that’s not how they accomplish their most important job. See, vaccines can’t be given to every individual—babies can’t get MMRs until they’re 12 month old, for instance, and many people on chemo or after transplants can’t get them at all. And even the absolute best vaccines don’t work all the time. Two doses of MMR gives 99% of recipients lifelong immunity from measles, but if you’re at Disneyland along with 40,000 other visitors that day, it means about 400 vaccinated people (1%) are not immune. That’s not a slam on the vaccine—it’s just that any medical intervention is imperfect.

So if vaccines don’t work by protecting vaccinated individuals, how do they work? By protecting populations. In a highly vaccinated population, even if measles pops up it’s got nowhere to go. If only a small number of people aren’t immune, it’s unlikely anyone else will catch it—and that means measles cannot spread, and everyone is protected. Not just the immunized, everyone. This is called “herd immunity”, and it’s the real way that vaccines work.

Vaccines aren’t about protecting just you, or your children, or just the person who gets the vaccine. Vaccines are about protecting all of us, even the babies, and the ill, and the unlucky few in whom vaccines don’t work. We’re all in this together. Maybe you’ll be the next in the neighborhood with a newborn, or maybe it will be your sister who’s diagnosed with lymphoma. Make sure your whole family is vaccinated to keep all of us safe.

 

Myth 2: Children are required to be vaccinated.

Nope. Children are required to be vaccinated in order to attend public school, just like you’re required to have a driver’s license if you want to drive. But you don’t have to get your children vaccinated as long as you make other arrangements for their education.

Even then, there are plenty of exemptions. Every state supports exempting children with legitimate medical contraindications to vaccines; almost all states support “religious objections” (though there is no common religion that’s against vaccines); many states also offer “personal belief” exemptions, too.

No government authority is forcing anyone to vaccinate, and no children are being taken away from parents who don’t vaccinate.

 

Myth 3: Vaccination, inoculation, immunization—they all mean the same thing.

In common usage, yes. But technically, they’re different.

Inoculation initially referred specifically to the historical practice of rubbing the skin of a healthy person with a little bit of crust from a smallpox victim. It was known that this could often induce a mild case of smallpox, which would protect the person from a full-blown, deadly case later. These procedures were fairy widely known especially in England in the 1700s, and remained in widespread use for hundreds of years. The word inoculate comes from the Latin root for ‘eye”, referring to the practice of grafting a bud from one plant to another.

Edward Jenner later started using scabs from cowpox to “inoculate” a milder disease, which was close enough to prevent smallpox, too. It’s thought that his inspiration was the fair, unblemished skin of English milkmaids—they universally caught cowpox as an occupational hazard, so rarely caught the disfiguring smallpox. “Vaccine” comes from the Latin word for cow, either referring to cowpox or perhaps to those fair-skinned milkmaid workers. For a while, the term “vaccination” referred only to using cowpox crusts to prevent smallpox, but later the term became more generalized to include the procedures developed by Louis Pasteur to prevent chicken cholera and anthrax.

Immunization was a later term that broadly referred to both using live infectious particles to induce active immunity, or using non-infectious toxins or other proteins. Typically, now, most of us use the terms vaccine, vaccination, and immunization pretty much interchangeably. Next time your children get one, thank a cow!

Some bad news about flu this year

December 8, 2014

The Pediatric Insider

© 2014 Roy Benaroch, MD

We could be in for a rough influenza winter.

First, data just released from the CDC shows that a lot of the flu circulating in the USA isn’t a good match for the strains in this year’s flu vaccines. About 82% of flu since autumn is a type A H3N2, one that historically has been associated with more-severe illness. Of those, only about half are closely related to the A/Texas/50/2012 strain that was chosen in February to be included in the vaccine. Unfortunately, current methods of vaccine production take a long time, and manufacturers have to commit early—months ahead of time—to what will be included in the vaccines. In February, when the World Health Organization made their recommendations for the Northern Hemisphere 2014-2015 flu vaccine, they chose the H3N2 that was then in circulation. Since then, it’s “drifted”, or changed, to a related but non-identical type.

What this means is that the current vaccine is well-matched to only about 40% of circulating flu. The vaccine will probably offer some protection against the other 60%– illness will be milder and shorter—but a lot of people who got their flu vaccines are still going to get the flu, and spread the flu. Now, some protection is still better than none, so I’d still go and get that flu vaccine now if you haven’t gotten it already. An imperfect (or, honestly, far-less-than-perfect) flu vaccine is better than none. But it isn’t looking good this year.

And it gets worse. It’s becoming increasingly clear that Tamiflu, the anti-viral medication we rely on to help treat influenza, doesn’t work very well. As summarized by the Cochrane Collaboration earlier this year, studies show that Tamiflu is only modestly effective in reducing the length of influenza illness, and may be only slightly effective at reducing complications. If it does work for treatment of flu, it works best when started very early in the course of the illness. The FDA labeling calls for it to be started within 48 hours, but honestly it seems to barely work if started that late. Better to get it started within 24, or even better, 12 or 6 or 2 hours.

In practice, Tamiflu really doesn’t seem to do much of anything for most of the flu patients seen in hospitals and doctor’s offices, because we usually see patients too late. It does have a role in helping family members at risk for flu. They can start it immediately, at the first symptoms, and will probably get more benefit.

Tamiflu can also be used as a prophylactic, or preventive, agent in people exposed to flu with no symptoms, though again, the benefits are modest at best. Crunching the numbers, we probably have to treat about 33 people on average for just one person to benefit from prophylaxis. That’s not very good, especially considering that all 33 people will have to pay for it and risk the side effects.

And Tamiflu does have some significant side effects. Nausea and vomiting are quite common, but the scarier reactions are depression, hallucinations, and psychosis. Neuropsychiatric side effects are most common in people of Japanese ancestry.

So: the flu vaccine, this year, will probably offer only modest benefits. And Tamiflu really has very limited usefulness. It looks like we’d better prepare for a rough winter, and keep in mind some of the old-fashioned ways to keep from getting the flu:

  • Stay away from sick people.
  • If you’re sick, stay home.
  • Keep your mucus to yourself—sneeze into your elbow, or better yet into a tissue. And then wash your hands.
  • Don’t touch your own face. Flu virus on your hands doesn’t make you sick until you help it get into your body by touching your eyes, nose, or mouth.
  • Wash or sanitize your hands frequently, and especially before touching your face or eating.

Infection Report 3: The single biggest infectious health risk is preventable

October 8, 2014

The Pediatric Insider

© 2014 Roy Benaroch, MD

Here’s what people are dying of in the United States, in order: heart disease, cancer, chronic lung disease (mostly COPD, usually among smokers), stroke, accidents, Alzheimer disease, diabetes. And at number 8, the first infectious cause of death on the list: influenza and pneumonia, about 54,000 deaths a year.

(By the way, at least some cancers are infectious diseases, and two of those we can prevent with vaccinations. But let’s focus on influenza and pneumonia here.)

The most common fatal complication of influenza is pneumonia, so it can be difficult to tease out how many of those 54,000 “pneumonia and influenza” deaths were caused by influenza. Influenza also contributes to death by many of the other causes (it is the final straw in many patients with COPD or other health problems.) It’s likely that influenza viral infections are the proximal cause of about 36,000 deaths a year in the United States.

Unlike Ebola, influenza spreads rapidly in a community. Influenza virus can be spread by sneezing or coughing, or even better by mucus left on surfaces and doorknobs. Also, unlike Ebola, people with influenza become infectious a day or so before they’re obviously sick.

There are simple steps you can take to prevent contracting and spreading influenza. Most importantly, people with influenza symptoms shouldn’t go to school or work. Keep your mucus to yourself, as much as you can, by sneezing into tissues and using hand sanitizer to clean your hands. Remember, influenza virus gets from place to place on hands—once deposited somewhere, it doesn’t jump up and fly around. You have to touch it, then touch your own face, to get sick from influenza virus.

One more step that we all need to take: make sure you and your family get influenza vaccinations! The vaccine is terrifically safe, and it works well most of the time to  reduce the transmission, rate, and severity of influenza. Taken as part of an overall influenza prevention scheme, vaccination is an essential step.

The CDC recommends influenza vaccinations for all of us, everyone over six months of age. That’s because the more people get the vaccine, the more all of us are protected. It doesn’t work 100% of the time, and young babies and people with some health conditions can’t be vaccinated—so it’s up to the rest of us to keep vaccination rates high, to protect everyone. One lesson is clear from the current media hysteria over Ebola, Enterovirus D68, and other new infections: we’re all in this together. Influenza is one infection that we’ve got the tools to beat.

Tomorrow: more new infections that are making the headlines.

More info:

Flu myths

CDC comprehensive flu info

There are no kangaroos in vaccines, either

November 18, 2013

The Pediatric Insider

© 2013 Roy Benaroch, MD

Let’s say you were inventing a new flea powder, called Flea-B-Gone. To test it and manufacture it, you’d need a whole mess of fleas. As everyone knows, kangaroo fleas are hardy and docile, so you open up a kangaroo farm to grow your fleas. You treat the kangaroos well, and other than itchiness, they don’t have much to complain about as you scrape off their fleas to make your Flea-B-Gone. Again: no kangaroo parts end up in Flea-B-Gone. Just the fleas.

Would a reasonable person claim that Flea-B-Gone contains kangaroos?

Wait—what if your great-great-great (repeat that a thousand times)-grandmother actually started this business with her pet kangaroo, Kanga-Ook. Over thousands of generations, Ook had babies who grew up on the farm, who then had babies, and all of them grew up to be flea-wearing kangaroos. Thousands, maybe millions of generations later, would you say that modern Flea-B-Gone contains the ancient ancestor of your current kangaroo stock, old Kanga-Ook?

Anti-vaccine propagandists have a stock litany of claims, sort of a rogues gallery of misinformation that they’ll repeat, endlessly, hoping to fool someone into taking their side. When one claim is obviously known to be false, they’ll move on to the next one, until they recycle back to the beginning. This endless whack-a-mole leaves parents stunned and confused, which is the point of the anti-vaccine crowd. Confuse, obfuscate, pretend there is controversy where there is in fact none. Parents get scared of vaccines, and in some sick way I suppose the antivaccine people think they’ve won.

Today’s false claim: that vaccines contain “aborted fetal cells.” It’s an obvious lie, which would be clear to anyone who remembers middle school biology class. Still, it’s an ugly sort of phrase, aborted fetal cells, and it sticks. But vaccines don’t contain any “aborted fetal cells” any more than Flea-B-Gone contains parts of an ancestral, million-years old kangaroo.

Some (not most) vaccines rely on actual viruses for production. The viruses are “grown” on cell cultures, which are sort of like the kangaroos. The cell cultures themselves come from cells that were harvested in the 1960’s, sometimes from fetal tissue, and sometimes that tissue was obtained after an abortion. Those cell lines have been propagated for forty or fifty years, dividing and creating new cells, millions of generations of cells, in thousands of labs. Since these cell lines have been used for so many years, they’re dependable and well-known, and can be used to safely grow viruses. These same cultures are also used in medical and research labs all over the world. They are an indispensible tool that we take for granted, but we rely on them for medication development and biologic research every single day.

No vaccine contains any of these cells. They’re used to grow the viruses needed to test and develop vaccines, but they’re not in the vaccines. And: the cells themselves aren’t aborted tissue any more than a kangaroo is the same animal as an ancestral kangaroo that hopped around Australia millions of generations ago.

Current cell cultures are not aborted tissue. And even if they were, they’re not contained in vaccines anyway.

These are important decisions. Refusing to vaccinate your children is hurting children, families, and communities. If parents knew the actual facts, they’d sleep easier, they’d vaccinate, and we’d all be healthier. Don’t buy the propagandists’ lies. Vaccinate.

PS. The Vatican responded to these concerns in 2005, in a statement created by then-Cardinal-Ratzinger, who became Pope Benedict. It’s fascinating reading. FWIW, the Vatican’s position is that every effort should be made to not use these cell lines, but that the “good” of vaccinations—to protect health—outweighs the original “evil” of how the tissues were obtained 50 years ago. So, until alternatives are available, families ought to vaccinate using these products. The statement did not directly address the issue of the kangaroos.