Dr. Bob Sears Gets it Wrong Again

This time, about pertussis, pertussis epidemiology, vaccinology and well, just about anything else to do with pertussis. Here is a recent post by him on The Vaccine Book Discussion Forum and his FaceBook page entitled, Pertussis Epidemic 2010: What Should Parents Do? I will break the entire post down point by point. His unedited post appears as indented text.

With the current increase in pertussis (whooping cough), many parents with unvaccinated children are naturally wondering if they need to worry. Here are some of my thoughts:

There IS an increase this year, but pertussis naturally shows a temporary rise for about a year or two every 5 years. The last such increase was in 2004/2005, followed by a decline back to normal. So it’s no surprise that this has happened. It’s not like we are unexpectedly seeing a sudden epidemic. We KNEW this was going to happen. That doesn’t make it any less serious, but it’s important to know that pertussis naturally rises like this.

In past years we’ve had about 15,000 reported cases of pertussis each year. The every-five-year peaks we’ve seen have been about 20 to 25,000 cases. This year we are looking at 30,000 or more. However, these are just the reported numbers. Only about 10% or less of cases are actually diagnosed or reported. So the real numbers are MUCH higher. So, these periodic increases could be mostly increases in reporting, and not much increase in actual disease. Or it could be disease increase. It’s hard to say. One argument if favor of an actual increase is that we do know the actual fatality numbers very accurately. And when that jumps higher, as it has this year, we can take that as a likely indication the disease incidence is higher as well.

Dr. Sears doesn't grasp basic principles of epidemiology such as it isn't the unexpectedness that defines an epidemic, it is the increase in the expected number of cases. Pertussis epidemics occur in 3-5 year cycles, but why? This observation isn't unique to pertussis but many diseases that we are familiar with and have successfully controlled with vaccination, such as measles. Pertussis is cyclical because of highs and lows in herd susceptibility, not due to changes in the bacterium itself. So pertussis infections, such as in 2004/2005, spread through the population because a critical mass of susceptible people have accrued due to births, decreased vaccination rates, primary vaccine failure (the vaccine did not confer adequate antibody titres in the recipient) and secondary vaccine failure (vaccine immunity has waned to below protective levels) and waning natural immunity.

Pertussis is a vastly under-reported disease due to misdiagnosis, underdiagnosis, and asymptomatic and subclinical cases. However, it is under-reported rather consistently so we do know that we are experiencing an epidemic year and not a change in reporting. There is absolutely no evidence that reporting efficiencies would have such a consistent cyclical nature. Case fatality rates are not a consistent indicator of disease incidence rates either.

Is this rise due to so many unvaccinating families? Not in my opinion. The primary reason for the rise is that pertussis is a stubborn germ, and it’s difficult to make a highly effective vaccine against it. The vaccine has an estimated efficacy of 80 to 90%. This is much lower than most vaccines. So outbreaks will occur in both vaccinated and unvaccinated children. Another reason is that the vaccine wears off, so teens and adults can easily catch whooping cough. They might cough for a few weeks without realizing they have it, and spread it around to other adults and children. There are far more teen and adult cases each year than childhood cases.

His opinion should be qualified by evidence and it isn't. Vaccine efficacy has nothing to do with pertussis being a 'stubborn germ'; there is no such accepted or recognised term. The vaccine efficacy, which incidentally is ~63-100%, is due to limitations within the vaccine construct and host immune response. Naturally-acquired immunity does not confer much longer immunity than the vaccine. Which is all more reason why very high vaccine uptake amongst those eligible is crucial to protect vulnerable infants that are too young to receive the vaccine or complete vaccination.

Let's look at some recent figures from the 2010 pertussis outbreak. Here are the California Department of Public Health's pertussis statistics for 2010 by county and here are vaccine exemptions for 2009 kindergarten entry. There has been much finger-pointing at Marin County due to their high rates of vaccine refusal. Not only has their vaccine exemption rate nearly doubled since the last pertussis outbreak to over 7%, but vaccine uptake by kindergartners has steadily fallen below threshold levels to 83%. This is not all though; there is substantial clustering of extremely high vaccine refusal for certain schools. For example, more than half of San Geronimo Valley Elementary and Marin Waldorf School students have vaccine exemptions. Marin County also tops the list for pertussis case rate at 99.8/100,000.

Counties also reporting the highest pertussis case rates/100,000 are San Luis Obispo (98.90), Del Norte (52.23), Madera (37.91), Fresno (31.30) and Colusa (30.04) with respective vaccine exemption rates (%) of 3.92, 5.75, 1.06, 0.98 and 0.54. These counties aren't demographically or socio-economically similar to Marin county at all, so what is going on? With the exception of Del Norte county, the rest are located in California's Central Valley, which is highly agricultural and/or has large sub-populations living at or below the poverty level. This situation translates to disparities in access to health information and services. Numerous San Luis Obispo county schools also have high vaccine exemption rates. Thus, high rates of pertussis infection are still occurring in areas with pockets of low vaccine uptake, but for different reasons than in Marin. It is interesting to note that Del Norte county's pertussis cases for 2010 were all reported prior to May and no new cases have been reported since then following a county-wide immunisation programme.

While it isn't as simple as 'high rates of vaccine refusal linearly corresponds with pertussis cases', as there are numerous factors involved, it is safe to say that vaccine refusal does contribute to increases in pertussis, regardless of the reason. So if Dr. Bob's advice makes him feel uncomfortable about promoting lower vaccine uptake, then perhaps he ought to spend a bit more time investigating the potential ramifications of his advice as should parents taking his advice.

Do unvaccinated children put others at risk? I would have to say that this is true to some extent. An unvaccinated child IS more likely to catch pertussis than a vaccinated child. So it makes sense that the fewer children that are vaccinated, the more likely the disease is to go around. However, this doesn’t mean that anyone has a right to put blame on unvaccinated kids or their parents. Some parents just don’t feel comfortable with vaccines, and they have the right (in this free country) to decline vaccines in most states. Because every vaccine has the potential to cause very severe, even fatal, reactions (which are extremely rare), parents have the right to avoid the vaccine and risk the disease instead. Parents who do feel comfortable vaccinating will get their children protected so they are unlikely to catch the illness if exposed.

Not surprisingly, Dr. Bob contradicts himself by admitting that unvaccinated people do put others at risk and increase disease circulation, but yet are not responsible for the increase in pertussis cases. It doesn't matter why parents are refusing vaccines for themselves and their children; it matters how many and their geographical distribution. So even while parents have the right to refuse vaccinations, that doesn't make them any less culpable for their contribution in the rise in incidence of diseases. Just as it doesn't make any physicians or pseudo-doctors (e.g. chiropractors and naturopaths) any less culpable for promoting vaccine refusal for bogus reasons and deceptively inflated risks.

The children of vaccine refusers are 23 times more likely to contract pertussis infection than in vaccinated. And states that allow easily-obtained vaccine exemptions were associated with a higher incidence of pertussis and numerous other studies have demonstrated that vaccine uptake is inversely correlated with pertussis infection.

How serious is pertussis? The disease usually kills about 20 babies each year in the United States. This year, with the increase, we are headed for about 30 or maybe 40 deaths. These are very tragic. ALL fatalities from pertussis over the last few years have occurred in infants 3 months and younger. For many years before that all fatalities were in infants 6 months and younger. These young babies have about a 1 in 200 risk of fatality if they catch the disease. Fortunately, most babies who catch it will be just fine. Some will need hospitalization, and about 1 in 200 may die. Again, while this is tragic, this is a much lower fatality rate than some of the more serious infant infections such as meningitis.

What about older infants and children? Do parents need to fear for their safety? NO. Infants older than 6 months really have almost zero risk of fatality. Toddlers and preschoolers and older kids virtually always handle the illness without any trouble. Sure, they’ll cough for a month or two, but complications are extremely rare at this age, and hospitalization is unlikely.

Dr. Sears seems to be downplaying the complications associated with pertussis infection by emphasising the only outcome of interest being death. A case fatality rate of 1 in 200 is very serious and that alone puts the risk of disease and death orders of magnitude greater than the risk of death from vaccination. Seventy-nine percent of infants less than 6 months old have required hospitalisation, while 21% of hospitalised pertussis cases have been in > 6 month olds. One in 250 children with pertussis will have permanent brain damage, 1 in 10 will acquire pneumonia. So technically, yes, most children will be fine but why take the chance of risking weeks of very unpleasant illness and having no guarantee that your child will be fine. His comparison to meningitis is also disturbing. If most, if not all future deaths and serious sequelae from pertussis disease can be avoided with increased vaccination then it doesn't matter what statistics other pathogens present. Preventing pertussis disease and meningitis are not mutually exclusive.

One thing that has bothered me is that the media is making it sound like there’s a deadly pertussis epidemic, and that all kids are at risk. This is scaring parents and children of all ages. What the media really should be saying is that parents with new babies need to worry, but parents with older children don’t. There’s very little harm in catching this disease outside of infancy.

Dr. Bob is now instructing 'the media' (although he doesn't specify the sources) to present a portrayal of the current pertussis epidemic that won't make his recommendations look so bad. Who does he think that pertussis reservoir is? How are infants, too young to be vaccinated going to be protected if there are large clusters of unvaccinated or susceptible people surrounding them? The pertussis rate/100,000 in infants and children 6 months to 18 years old is 45; this isn't just a disease in infants. There is very little harm in catching the disease outside of infancy? I beg to differ. Again, it appears as though Dr. Bob's 'feel good' advice about vaccinations is coming back to haunt him and he is rather uncomfortable.

SO WHAT SHOULD PARENTS DO?

First, if you are planning to vaccinate, your infant will receive the DTaP vaccine at 2, 4, and 6 months of age. In certain areas where pertussis is highest, doctors do have the option of vaccinating early – at 6 weeks, 10 weeks, and 14 weeks of age. One dose of the vaccine doesn’t work very well, so the sooner a baby gets the third dose the better he’s protected. Ironically, by the time an infant receives the 3rd dose at 6 months (on the regular schedule), he is beyond the risky age for pertussis. I don’t really have an opinion on whether or not parents who live in high pertussis areas should get the accelerated schedule. That’s between you and your doctor. I have not begun doing the faster schedule, and don’t have any plans to do so at this time.

Six months of age is not "beyond the risky age for pertussis", they are just as susceptible without full vaccination. They are less likely to experience fatalities after 6 months, but they don't magically become risk-free for hospitalisation or serious sequelae. Twenty-one percent of children and infants over the age of 6 months in the current epidemic are still being hospitalised for complications.

Second, because new babies are vulnerable to pertussis in the early months before the vaccine is started and completed, parents and caregivers do have the option of getting the Tdap vaccine (a teen and adult version of the DTaP vaccine). New moms can get this when the baby is born, and dads can too. It’s given as a single dose. It’s ok to get if breastfeeding. You can review the details on this vaccine (how it’s made, what the ingredients are) in The Vaccine Book. I don’t really have an opinion yet on whether or not all parents and caregivers should get this shot. As a pediatrician, I don’t give adult shots, so I don’t have experience on how parents are tolerating the vaccine. But I do feel that the theory of giving parents of new babies this vaccine has merit.

Alas, something that almost makes sense. However, his advice is incomplete as children that have either not received vaccination with DTaP or boosted with Tdap at the appropriate age are not mentioned. The California Department of Public Health is recommending children 7 years and up receive Tdap as a booster so there is no gap in age-appropriate vaccine. So older siblings can be vaccinated either with the primary series or boosted in order to reduce transmission to household contacts as well as the general public.

Third - What about parents who are undecided about giving their new babies this vaccine? Is the current outbreak a concern? There is more risk of catching pertussis this year than last year, and this risk is likely to decline again next year as pertussis naturally wanes (if it follows the pattern of the past couple decades). Parents can review all the pros and cons of this decision in The Vaccine Book.

Nothing like a solid recommendation to try and keep infants safe during a pertussis epidemic. What does such a mealy-mouthed statement do for parents right now? The only reason that pertussis cases will decline the following year is that so many have been infected this year.

Fourth - What about unvaccinated OLDER infants, toddlers, and children? I’ve had a lot of my unvaccinating families call my office and ask if they should NOW get their children vaccinated. Here’s what I’m telling them:

• Realize that pertussis isn’t dangerous beyond infancy. It isn’t fun, and the coughing spells can be tough, but it isn’t dangerous. I can’t say an exact age at which it becomes “safe” to catch pertussis – there’s a gradually decreasing risk once a baby turns 6 months. So, an unvaccinated older infant or child doesn’t necessarily need the vaccine for HIS own protection (see below for other reasons to get the vaccine), and parents don’t need to “fear” this disease beyond infancy.

This is such dangerously bad advice as to be medical malfeasance. Paroxysmal coughing fits can last for weeks and cause cyanosis, vomiting, sleeplessness, rib fractures and cranial bleeding, even in older children and adults. Dr. Bob is contending the sin of omission is better than the sin of commission to validate his evidence-free recommendations. Again, why put children through any amount of misery, that could lead to serious complications, when vaccination can likely prevent that from happening and the risks of vaccinating far outweigh the risks of serious disease sequelae?

• Families with unvaccinated children who have a newborn or young infant should consider vaccinating their older children. Many families who skip vaccines do so because they worry that their little babies can’t handle them as well. Once a child turns two years or older, such parents might become more comfortable and vaccinate the child before a next baby comes along.
• Even without another little baby joining the family, parents could consider giving an unvaccinated older infant or child this vaccine series to help lower the chance that their child might catch it and spread it to other babies in other families.
• Children need at least 3 doses to have useful protection. Any undervaccinated child will have some protection, but should be considered susceptible. It isn’t clear if partial vaccination even helps lower the severity of the disease (as it does in chickenpox, for example).

There is nothing magical about 2 years old as infants respond well to DTaP vaccination and certainly no reason to cater to parental fears about vaccinating. Rather, provide them with accurate information about vaccines and effectively communicating risk assessment.

• In my own office I’ve seen a few patients come in for vaccination because of this outbreak, but I would say most patients who initially skipped the vaccine are not changing their mind now.

A final note: realize that DTaP is only approved for use through six years of age. Once a child turns seven he’s too old for it. Safety and efficacy have not been studied beyond six years of age. The teenage Tdap vaccine isn’t approved until a child turns ten years old. So, children age 7, 8 and 9 can’t get a pertussis vaccine.

Ultimately, I can’t make the decision for you. You need to review that chapter in the book and consider the above information. Then make an informed decision.

Dr. Bob does not seem to be taking this epidemic very seriously. He is essentially suggesting that parents who have chosen not to vaccinate their children have no reason to re-assess the current situation and act accordingly. He is far too interested in coddling and perpetuating parents' emotional beliefs (and maintaining book sales) than he is in acting like the expert he purports himself to be and to also, advise his readers to discuss the matter with their actual physician. Instead, he recommends that you buy his book.

Dr. Bob practises in California and has undoubtedly received the CDPH recommendation for vaccination of 7 year olds with Tdap and safety and efficacy have been determined. How can he advise parents to make an informed decision when he doesn't provide accurate information?

Addendum (added 8.10.2010): Dr. Bob has added a note to his posts regarding Tdap recommendations:

Well, I just got a note from Sanofi-Pasteur announcing that the Califonia Department of Public Health announced that their brand of Tdap (Adacel) has been temporarily approved for use in california children ages 7,8, and 9 years. This wasn't part of the FDA approval process, but the California government feels that the benefit of having a pertussis vaccine for this 3-year age group outweighs the fact that it isn't actually approved or studied in this age group. Just FYI.

The California Department of Public Health issued their recommendation on or shortly after 16 July 2010. While it is true that the use of Tdap has not been FDA approved, it is completely false that its use in younger populations has not been studied for safety and efficacy. The Public Health Agency of Canada recommended the use of Tdap in children 7 years and older in 2006 so it has an established safety profile. In light of pertussis epidemiology in California and elsewhere, it is rather curious that Dr. Bob would not be more abreast on current issues involving pertussis vaccination and appears to be lobbying against the current recommendation with no valid support to do so.

Dr. Bob is attempting to balance his reputation as a non-vax friendly doctor with the very real danger of infants and children suffering pertussis fatalities and serious complications. Instead of providing explicit and accurate recommendations to parents, he invokes abstract dangers of vaccinating and then gives parents the non-advice of, "well it's your decision", thereby freeing himself of any responsibility. Rather than being focused his own image, Dr. Bob should give greater concern to the well-being of the children of those who follow his advice.