Posted tagged ‘vaccines’

Great news about cancer prevention!

October 6, 2016

The Pediatric Insider

© 2016 Roy Benaroch, MD

The first large, population-based study of real-world changes in cervical cancer screening in the era of HPV vaccination has delivered some great news: the HPV vaccine not only works, but it’s working better than expected.

Researchers looked at rates of CIN, the growth of abnormal cells in the cervix detected by Pap smears, among young women in New Mexico. Even though fewer than 40% of eligible women had received all three doses of the HPV vaccine, rates of these pre-cancerous lesions dropped by over 50%. That’s a huge impact. A safe intervention has cut the incidence of a common cancer by 50%, even in a community where HPV vaccine uptake wasn’t very good. It’s great news, and it hints at even greater news: if we can get more people vaccinated, this cancer-preventer can work even better.

Why did the vaccine work better than expected? There’s a herd effect, where vaccinated individuals help protect everybody by preventing spread of the virus. Plus, the vaccine seems to offer at least some protection against related strains. And it turns out that even women who receive less than the recommended three doses get at least some helpful immunity.

The most-used HPV vaccine in the United States goes by the brand name Gardasil-9, and it protects not only women, but men, too—especially from many cancers of the mouth and throat. Since there’s nothing analogous to a Pap smear for men, it will take longer to see these kinds of cancer-beating effects in the male population, but initial studies relying on rates of infection look very promising.

The HPV vaccine is very safe, and it’s already having a big positive effect in communities. Unfortunately, some parents have been scared away from this vaccine by irresponsible and often flagrantly false internet rumors. Don’t believe the scaremongers. Protect your kids from cancer by making sure they get their HPV vaccines.

Here’s a detailed and well-referenced post from The Skeptical Raptor explaining far more about the Gardasil vaccine, and debunking many of the myths being used to scare parents.

 Q&A from the CDC about HPV and HPV vaccinations


MERCK - Merck's HPV Vaccine, GARDASIL®9, now available in Canada

Goodbye, Flumist: Why science is important

June 23, 2016

The Pediatric Insider

© 2016 Roy Benaroch, MD

Yesterday the CDC announced that its Advisory Committee on Immunization Practices (ACIP) voted to stop recommending the nasal spray flu vaccine, Flumist, for anyone. Bottom line: it doesn’t work. Though their recommendation against the use of Flumist still has to be approved by the CDC director to make it “official”, it’s pretty much a done deal. The AAP’s president has already endorsed the announcement, too.

Bye, Flumist. We’ll miss the ease of use and the not-scaring-children part, but the data’s clear. The mist doesn’t work. There was a sliver of good news, though—we have solid surveillance data from last year re-confirming that the traditional flu shot does work, with an estimated effectiveness of 63% last year. That’s not outstanding, but it’s pretty good. From a public health point of view preventing 63% of influenza cases can have a huge impact. Remember: every case prevented is one fewer person out there spreading influenza. Effective vaccinations not only help the person who got the vaccine, but the whole family and community.

Older data, at one point, had shown that Flumist was as effective (or even more effective) than the flu shot. For a few years, the mist was even considered the “preferred product” for children, because it seemed to work better.  Last year, Flumist lost its “preferred” status when data emerged showing that it wasn’t looking as good as the shot. Now, enough newer data has accumulated to show that at least against the strains that have been circulating recently, Flumist doesn’t work at all.

There’s going to be a scramble (again!) this year to ensure an adequate supply of injectable flu vaccine. I don’t know if MedImmune will suspend the Flumist program, or if they’ll still try to sell their product – but I am sure that there are a lot of docs out there scrambling this morning, trying to cancel Flumist pre-orders and increase our orders for alternatives. In the long run, that will be better for everyone. In the short run, it’s a problem. Families ought to plan to get their flu shots as early as possible this year, before they run out.

Science isn’t a set of answers, or a body of knowledge etched on a stone somewhere. It is a method of arriving at the truth, involving repeated observations and the continuous re-assessment of data. Estimates of vaccine effectiveness (and safety) are initially based on licensing studies, but they’re then adjusted by real-world data that continues to be collected, year after year. We should always make the best decision we can, based on the best data, even if that means we have to sometimes admit we’ve made a mistake, or that we have to change our minds. That’s not a weakness of science or medicine – that’s a strength. We can’t always promise to get it right, but we’ll keep studying and learning and trying to do it better.


Serious allergic reactions to vaccines: Something else not to worry about

April 18, 2016

The Pediatric Insider

© 2016 Roy Benaroch, MD

A huge study of over 25 million doses of vaccines has shown that serious allergic reactions are super-rare, and even when they do occur they’re typically easy to treat.

Published in the October, 2015 edition of The Journal of Allergy and Clinical Immunology, the study looked at a huge database of 17,606,500 visits for a total of 25,173,965 vaccines. This is seriously Big Data, people. After all of these vaccines, only 33 cases of a severe allergic reaction occurred. Even among those 33, only one child required hospitalization, and none died.

More reassurance: there were zero serious reactions among children less than four years of age. And most of the 33 reactions (85%) occurred in children who had a history of other allergic diseases.

Despite its rarity, anaphylaxis is a potentially serious reaction. If your child experiences a widespread rash, trouble breathing, severe GI symptoms, or fainting after a vaccine, it might be an allergic reaction – a medical evaluation is needed. Most of these reactions won’t turn out to be serious or life-threatening, but they do need attention. Almost all teenagers who faint after vaccines have just fainted, and will be fine, but they need to be watched and their blood pressure checked. If further evaluation shows it’s an allergic reaction, medical therapy given quickly can help stop the reaction.

But: we need to keep these reactions in perspective. They’re really phenomenally rare. 33 out of 25 million vaccines means that your children have a higher chance of being hurt in a car accident on the way to their appointment than of having a serious allergic reaction to a vaccine. Other, non-allergic but serious reactions are really very rare, too. The internet has made otherwise well-adjusted people into parents worried stiff over vaccines. Don’t let it happen to you. Don’t live in fear and worry. Immunizations save lives, they’re safe, and they’re something you don’t need to worry about.

Wemberly Worried

The cost of fear

March 21, 2016

The Pediatric Insider

© 2016 Roy Benaroch, MD

The image of a “mad scientist” can be hard to shake: a deranged man with crazy hair in front of a row of bubbling test tubes and antennae shimmering with a ghostly electric glow. BWAHAHA, my monster is alive!

Real science, of course, has nothing to do with any of that. But it still sparks fear, and that fear has consequences.

One of the best ways to fight Zika virus is to reduce the mosquito population. We’ve got tools – already tested, already shown to be effective and safe – to use releases of sterile mosquitos to stop breeding populations. But we’re afraid to use them.

Parents fearful of vaccines put their own children, and their communities, at risk. One example: diphtheria, eradicated in Spain for 30 years, returned and killed an unvaccinated child. At least 8 other children contracted the diphtheria bacteria, but none of those other children became ill. They had been vaccinated.

Zimbabwe, facing a horrific drought with millions of starving citizens, has announced that they’ll accept no food aid that includes genetically modified organisms. They’d rather starve than eat food that’s often more nutritious and easier to grow with fewer resources. Here’s a funny and illustrative example of how far fear goes: they’ve explicitly banned GMO chickens, despite there being no GMO chickens in Africa, or anywhere else. They don’t exist. That’s what happens when fear makes decisions. Imaginary chickens, eek!

Zika is spreading, causing brain damage and other birth defects. Vaccine-preventable diseases have come roaring back. Ways to help feed the world are rejected. What do all of these follies have in common? Fear, stupid fear, making our decisions.

“So, first of all, let me assert my firm belief that the only thing we have to fear is…fear itself — nameless, unreasoning, unjustified terror which paralyzes needed efforts to convert retreat into advance.”

Franklin D Roosevelt, 1932


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

Vaccine reactions: How your “gut feelings” can fool you

November 23, 2015

The Pediatric Insider

© 2015 Roy Benaroch, MD

I’m struck, sometimes, by the vehement tone of some of the antivaccine comments you see out there. People who hate or distrust vaccines proudly proclaim that their Googling and life experiences have taught them that vaccines are bad. They don’t care what the science or the evidence shows. They know what they know.

Me? I’m not so much into vehemence and dogmatism. I’ll follow the evidence. Show me solid science that what I’m doing is wrong or harmful, and I’ll learn. I’ll let science—observations of the natural world—guide me, rather than what Facebook or Google or “my gut” says. Why? Because our guts can so easily be deceived.

A quick example: a baby gets vaccines, and five days later develops a health thing, like a life threatening allergy to peanuts, or a fever, or SIDS, or a rash, or a fussy night, or anything. The “logical” thing to do might well be to correlate one with the other. Baby got vaccine, a few days later something happened, so they’re related, right?

Wrong. Just because one thing follows another, one thing doesn’t cause another. In Latin, this is called the post hoc ergo propter hoc fallacy. An easy example:

My phone broke when I joined Netflix. So Netflix broke my phone. No, they’re probably unrelated. Phones break all the time, and people (used to) join Netflix all the time.

Babies in the first year of life have about 5 separate encounters for vaccines (it actually may be from 4-6, depending on timing and how the flu vaccine might be given, but we’ll just say “5”). So 5 of the 52 weeks of the first year of life – or about 1 in 10 — are, in fact, within a week following vaccines. Think about that. If anything bad happens in that week, and there isn’t another clear explanation, the bad thing may well be blamed on vaccines.

Statistically, about 1 in 10 babies who die of SIDS had a vaccine within the preceding week. That sounds scary, right? But in fact 1 in 10 ordinary, healthy babies from 0-12 months of age had a vaccine within the preceding week. There is no greater chance of dying of SIDS in the week following a vaccine than there is in any other week (in fact, vaccines are protective against SIDS—babies are less likely to die of SIDS if they’ve been vaccinated.)

Sometimes, a specific emotional story can frame a discussion. A friend of mine, a pediatrician, told me this story: his office was called at 4 in the afternoon by a mom who missed her baby’s 4 month well check appointment because their car broke down. No problem, she just rescheduled. But that night, her baby died of SIDS. That’s a terrible tragedy. What would the family had thought if that same baby had in fact gotten her vaccines that very day, and died that night? It was just a fluke that the car broke down. But you can imagine how the story might have played out on Facebook if the baby had been vaccinated that day.

And Facebook – we’re just beginning to realize how the expansion of social media is skewing our perception of the world around us. I’ve called this the “exaggerating freakiness” effect (I need to find a Latin phrase for that, or it will never catch on.) When an ordinary thing happens—and millions of ordinary things happen, every day—no one runs to the internet to post about it. But we love to post about the weird things, the unexpected things, and the one-in-a-million things. We don’t read about the millions of babies who get their immunizations without any problems. But we do read about babies who had issues after vaccines—whether or not the vaccines had anything to do with the problem. We can’t tell from Facebook posts whether one thing caused another, or even if the story is true. None of that matters. What we remember are stories that have emotional impact, regardless of what they mean about reality.

Parents do not need to worry about vaccines. They’re safe, they’re effective, and there is an extremely small risk of serious side effects—far outweighed by the good they’re doing keeping children and communities safe throughout the world. Don’t let headlines, click-bait, and emotional arguments trick you into worrying. Play it safe, protect your kids, and immunize.

Guest post: “Viral Shedding” is not something to worry about

June 22, 2015

The Pediatric Insider

© 2015 Roy Benaroch, MD

Today features the first-ever guest post at The Pediatric Insider, from a pediatrician buddy of mine. He wrote this as an open letter to Bob Sears, the most well-known vaccine doubting physician in the USA.  Thanks to the author for helping to fight unnecessary fear!


Hello, Bob Sears, M.D., FAAP.  Before I continue, I’d like to disclose that my sole source of income is from my employer* and that I am not selling any books (I haven’t written any).  I do not have any financial or business relationships with any vaccine manufacturer, nor have I ever accepted any gift from a vaccine manufacturer.  My only financial incentive with respect to vaccines is that I get a small (about 1.5% of my annual income) “quality of care” bonus from my employer at the end of the year if a certain percent of my patients are fully vaccinated according to CDC/ACIP guidelines.**  I’m writing and researching this post in my off time and I’m not expecting any compensation for it.

I just read this post of yours in which you raise concern that recently vaccinated patients might shed their vaccine viruses.  Certainly, I’m not familiar with this as a major danger to public health, so I decided to look into it.

sears bob shedding

As a fellow pediatrician, you are doubtlessly aware that only five types of live attenuated vaccines are currently use in the United States.  Those are the Live Attenuated Influenza Vaccine (LAIV), the two competing rotavirus vaccines RV1 (“ROTARIX”, GlaxoSmithKline) and RV5 (“ROTATEQ”, Merck), MMR, and the Varicella Zoster Vaccines.  These latter two are often combined into a single injection called MMRV.  As you are aware, the remaining routine vaccines (DTaP/TdaP, IPV, HBV, HAV, PCV13, HiB, MCV4, HPV4/9, IM/ID flu) are inactivated and incapable of shedding.(1)

We can ignore LAIV given that it’s June and I doubt anyone here in the Northern Hemisphere is currently using it.  That said, while 98% of recent vaccinees do shed LAIV, the rate of actual transmission is less than 1% (2).

As far as MMR is concerned, we know that the wild viruses are spread by respiratory secretions and that infection occurs by mucosal contact with the virus, but I was not able to find any cases in the medical literature documenting that the vaccine-strain Measles, Mumps, or Rubella viruses are shed in respiratory secretions after receipt of the MMR vaccine used in the United States or Canada.  I could find only a single report of possible vaccine-strain rubella (HPV-77 [unrelated to Human Papilloma Virus]) horizontal transmission from 1968 (3) and that did not result in symptomatic infection.  It is also possible that the seroconverted contact in that study actually had subclinical wild infection.  But I was also able to find a study in 1972 in which 67 rubella-nonimmune teachers were monitored after their classes of children were vaccinated and none showed evidence of seroconversion.(4)  Clearly, the risk of horizontal transmission of HPV-77 vaccine strain rubella virus is very low if it is not zero.

For the mumps component, I was able to find that the Leningrad-Zagreb mumps vaccine strain commonly used in Russia and India can rarely spread horizontally (5), and one case of the now disused Urabe mumps vaccine strain transmitted (6) but I was not able to find this for the Jeryl-Lynn strain used in the United States MMR vaccine.  Perhaps you have a reference that this has occurred?  If so I’d appreciate if you shared it.

It certainly is true that the vaccine measles strain may be shed in the urine of recently vaccinated individuals (7), but given that transmission requires mucosal contact this should not be cause for concern.  I certainly hope that nobody at your gathering will be drinking the urine of recently vaccinated infants!  In all of medical history since the time MMR has been in use there has only been one case report of horizontal transmission of the measles vaccine strain (8) and that was between siblings.  I cannot find any others, so I would say that this risk is so vanishingly small that it would be unreasonable to worry about it at a gathering like yours.

The other two live attenuated vaccines used in this country carry a bit more risk of horizontal transmission.  Cases of transmission of varicella zoster vaccine virus have been described (9) but in all of these cases, the individuals who transmitted the vaccine virus had a visible varicella-like rash and the recipients either had no symptoms or mild clinical disease.  There is, to my knowledge, one case of varicella vaccine transmission without a rash, but that was from a new mother to her infant(10).  It’s possible that it might have been transmitted in breast milk.  For this reason, both Merck and the CDC recommend that the <3% of children who do develop this rash be kept away from susceptible contacts until the rash resolves (10).  I’ll note than in ten years of clinical practice, I estimate that I have given over 2,000 doses of VZV either as a single-component vaccine or as the MMRV combination product and I am only aware of six such rashes in my patients (actually, one was in my medical student’s recently vaccinated wife who was not my patient, but I count her among the cases).  Thus, my own clinical experience has been about ten times better than Merck would claim.

Similarly, for rotavirus vaccine, the transmission rate to unvaccinated twins was 18.8% for the “ROTARIX” product in one placebo-controlled study in twins (11). But in these cases, these were twins living in the same household and having their diapers changed by the same parents.  It’s important to note that none of the transmission cases caused clinical gastroenteritis symptoms.  There is also a single case report of a recently vaccinated child with “ROTATEQ” transmitting a symptomatic infection to an unvaccinated older sibling (12), which resulted in an emergency department visit but no long-term sequelae.  Because transmission of rotavirus vaccine would only occur in very young infants (the vaccine should only be given <7mo) (13)(14), and the transmission is fecal-oral, simple good hand washing after changing a recently vaccinated infant’s diaper should reduce the risk of transmission to unvaccinated non-household contacts at a public gathering like the one you are holding.  Either way, the risk of transmission of a symptomatic case from a recently vaccinated child to an unvaccinated child appears to be vanishingly small, based on the available evidence.

But I also wonder why you would be so concerned about transmission of vaccine viruses at your event.  Perhaps you feel that people should consent to being exposed to infectious agents.  That would be nice, but that has never been the case.  My parents did not consent to my exposure to varicella at age 6 that caused me to spend a week in misery and left me with two scars on my face to this day.  Similarly, my parents did not consent to the exposure to (likely) rotavirus that hospitalized me as an 8mo infant.  Moreover, I have never consented to any of the symptomatic infectious diseases from which I have suffered as an adolescent or adult.  But certainly, as I have demonstrated, the risk of poor health outcomes after accidental exposure to attenuated vaccine-strain viruses is much lower than the risk for the wild-type viruses.  Yet you propose to have a gathering with a very high rate of unvaccinated children present.  To me, your risk-benefit calculation just doesn’t work out.

Perhaps you are concerned for any immunocompromised members of your audience, but we do not isolate recently vaccinated children and adults from contact with the general public, even though immunocompromised individuals live and walk among us.  They are as much at risk traveling to your gathering as they are at the gathering.

To further confuse matters, you have no way of knowing if any of the unvaccinated children attending your gathering might be in the asymptomatic but contagious prodromal phases the precede most symptomatic viral infections.  Diseases like measles and chicken pox are so contagious that virtually all children contracted them before the vaccines were available, even though it has always been policy to immediately exclude children with symptoms of these illnesses from attendance at school.

So perhaps you could explain your reasoning for this unusual restriction.  I’d appreciate it if you’d demonstrate that you have done your research as I have.


*I am technically an independent contractor.

**We get other “quality of care” bonuses for other “best practices,” like not treating viral infections with antibiotics, testing sexually active patients for STIs, and keeping problem lists in the medical record up to date.



(2) Vesikari T, Karvonen A, A randomized, double-blind study of the safety, transmissibility and phenotypic and genotypic stability of cold-adapted influenza virus vaccine. The Pediatric Infectious Disease Journal 08/2006; 25(7):590-5.

(3) Lefkowitz LB, Rafajko RR, et al. A Controlled Family Study of Live, Attenuated Rubella-Virus Vaccine — Seroconversion of a Susceptible Contact. N Engl J Med 1970; 283:229-232

(4) Fleet WF, Shaffner W, et al. Exposure of Susceptible Teachers to Rubella Vaccinees Am J Dis Child. 1972;123(1):28-30

(5) Atrasheuskaya A1, Kulak M, et al. Horizontal transmission of the Leningrad-Zagreb mumps vaccine strain: a report of six symptomatic cases of parotitis and one case of meningitis. Vaccine. 2012 Aug 3;30(36):5324-6

(6) Sawada H, Yano S, Oka Y, Togashi T. Transmission of Urabe mumps vaccine between siblings. Lancet.1993;342:371. doi: 10.1016/0140-6736(93)91515-N.

(7) Rota AS, Kahn AS et al. Detectin of Measles Virus RNA in Urine Specimens From Vaccine Recipients J Clin Microbiol. 1995 Sep;33(9):2485-8.

(8) Millson D. Brother-to-sister transmission of measles after measles, mumps, and rubella immunisation. Lancet. 1989; 1(8632):271.

(9) Tsolia M, Gershon AA, et al., National Institute of Allergy and Infectious Diseases Varicella Vaccine Collaborative Study Group Live attenuated varicella vaccine: evidence that the virus is attenuated and the importance of skin lesions in transmission of varicella-zoster virus. J Pediatr.1990;116:184–9. doi: 10.1016/S0022-3476(05)82872-0

(10) VARIVAX package insert, Merck.

(11) Rivera L, Peña LM, et al. Horizontal transmission of a human rotavirus vaccine strain–a randomized, placebo-controlled study in twins. Vaccine. 2011;29:9508–13. doi: 10.1016/j.vaccine.2011.10.015.

(12) Payne DC, Edwards KM, et al. Sibling transmission of vaccine-derived rotavirus (RotaTeq) associated with rotavirus gastroenteritis. Pediatrics. 2010;125:e438–41. doi: 10.1542/peds.2009-1901.

(13) ROTATEQ package insert, Merck

(14) ROTARIX package insert, GlaxoSmithKline