Reflecting the title of today’s blog…Phish performing Backwards Down the Number Line at the Mann Music Center, a few short minutes from my former home in Philadelphia.  For a different take, here is Trey playing a solo acoustic version of the song.

Backwards Down The Number Line

We have been anticipating the day where children were approved to receive a COVID vaccine, and that day is imminent.  We have all asked the same questions.  Is it safe for children?  Do they need it?  Should I give it to my child?  If you are reading this today thinking I will give you the answers, you clearly don’t know me well enough yet.  I will give you the facts.  I will give you some opinions, and be clear when doing so.  In the end, you will need to put on your thinking cap and make some choices.  The time may come where the answer is so clear that there are strong recommendations one way or another.  That time is not today.

Some old school metal from Iron Maiden for you.  After Ozzy, these guys were my favorite of this genre growing up.  Fun fact: Bruce Dickinson, the lead singer for Iron Maiden, is also an accomplished fencer.   Fun fact #2:  I saw Iron Maiden one Saturday followed by the Ramones the following evening at the Electric Factory in Philadelphia.  My ears rang for about one week and that weekend, while quite entertaining likely was the beginning of my development of hearing impairment

A Super Brief Disease Burden Update

All good news currently on this front.  Case numbers continue to plummet both nationally and locally.  Death rates are at pandemic lows, though not trivial at a bit less than 5000 deaths nationally per week.  Considering in January we were above 20,000 deaths weekly, this is great news.  As you listen to those that are attributing this to everyone being so good about mask wearing, observing some degree of restriction on activities, and getting vaccinated, I offer you one caution.  It is no longer coronavirus season.  I expect a fantastic summer for all.  It’s gonna feel quite normal in many regards again.  I myself cannot wait to hop on a plane in a month to head to Red Rocks Amphitheater to see Bob Weir and Wolf Bros for two nights in a row.  The real test of how well we did comes later this fall when coronavirus season warms up again.

An Equally Brief Update On Vaccine Coverage

At the time I am writing this, a quick Google search reveals that in the United States 33.1% of people are fully vaccinated.  An additional 12.3% have received one dose of COVID vaccine, bringing the at least partially vaccinated population total to 45.4%.  Considering that roughly 20% of the population has to date been ineligible to receive the vaccine, it means that 56.75% of the adult population has received at least one dose of vaccine.

Since we will discuss herd immunity next, selected a nice cheesy 80’s tune from a Flock of Seagulls.  Not a hair band…..but you could only get away with a hair style like that in the 80’s.

When Do We Get To Herd Immunity?

So what percentage of the population has to either have recent natural infection or vaccination to achieve herd immunity?  The super quick answer is that nobody knows.  I can tell you its more than 45.4% because that is the current vaccination rate in this country and we are still seeing significant albeit lower numbers of COVID infections and deaths.  Might it be 70% or 80%.  It might.  It might be never.  Sorry for that, but here is a very interesting read as to why that is the case.  Fundamentally, though, I don’t care if there is transmission of the virus, and nor do you.  At the end of the day, what you really want is that nobody should suffer serious illness or die from the disease.  Render it as much as a nuisance as the common cold, and we all win — and get back to dying from heart disease, diabetes, cancer, and various methods of earning Darwin Awards.

Can We Achieve Herd Immunity Without Involving the Kids?

Statistically…..maybe.  If only 70% of the population needs to be immune to achieve herd immunity, we would have a fighting chance.  If that percentage were 80%, it would require every adult in the country to comply.  About 1 out of 3 adults declines the COVID vaccine.  So realistically, the answer is no.  Worse yet, some illnesses have required 90% to achieve herd immunity, such as measles.  In such case, even 100% adult compliance with vaccination does not permit herd immunity without involvement of children in the process.  Before you all start tweaking out, because you clearly see where this is going, let’s look at some data and discuss.

Some mellow Coltrane to chill y’all out while we review data and discuss implications of COVID vaccinations for young-ins.

The Pfizer Trial in Adolescents

As we have discussed this in prior weeks, I will simply give a very quick review of the data that Pfizer has released as the basis for their request of the FDA to permit an emergency use authorization for adolescents 12 to 15 year of age.  The trial enrolled 2,260 adolescents, of which 1,131 received the vaccine and the rest placebo.  None of the vaccinated subsequently contracted COVID during the duration fo the study, whereas 18 of the control subjects did.  No severe side effects were noted, and those that occurred were similar to that which is seen in adults to date.  The common side effects are similar to those with other vaccines – headaches, fevers, chills, aches.

Theoretical Concerns

There are two primary sources of concern regarding the data released.  First is that the study was limited in size.  A study of the size conducted is limited to identifying side effects that occur in roughly 1 in 300 subjects.  Remember, we recently witnessed a vaccine rollout halted for a potential 1 in 1,000,000 side effect.  Do I really anticipate that there will be some exotic side effect in younger folks that was not experienced by the elders?  No, but I cannot say that based on data for this vaccine, rather I am relying on the historical track record for vaccines.

The second concern with the data release is that there were zero breakthrough cases.  Understand, if that truly held up over the long haul I would be ecstatic.  Realistically, there has never been a “perfect” vaccine, and there is no reason to think that Pfizer created one in this case.  Why do I care about breakthrough cases?  As discussed in previous weeks, there is a potential for a vaccine to potentiate the severity of infection in subgroups of the population.  More plainly stated, it is possible that if you get vaccinated and manage to get COVID despite, your outcome could be worse than having gone unvaccinated.  This happened once with a vaccine previously.  Once.  So again, do I expect this vaccine to potentiate infection in adolescents?  No, but I cannot say that again based on the data for this vaccine.

Wartux performing “Matter of Mind.”  Click here for a truncated acoustic version of the tune from 25 years ago performed by three med students messing around with a boom box to record. 

Reconciling the Risks of Potentiation

The risks of potentiation of disease with vaccinating children and adolescents against COVID is fundamentally different than the risks with Dengue.  The reason is that they are infections acquired in very different manners.

Dengue is contracted by transmission from mosquitos.  Even if you were to vaccinate an entire population, unless you kill all the mosquitos or prevent the mosquitos from carrying the disease, people will continue to be exposed.  Therefore, breakthrough cases will continue to occur, and the frequency of which will be unchanged regardless of how many folks are vaccinated.

COVID is an infection transmitted primarily from person to person (unless you are an Ozzy Osbourne impersonator and chomping on a bat’s head).  As the vaccine is clearly lowering the ability to contract the virus, the more people that are vaccinated, the less vectors for transmission.  Even in the case where everyone is vaccinated, there still may be low level transmission of the virus in society.  Severe disease in adults would rarely occur in such a situation.   In the case of adolescents, if transmission in society was lowered markedly by a vaccination campaign such as is ongoing, even if potentiation were an issue, it may be irrelevant.  Reason being that the reduction in numbers of adolescents ever being exposed would minimize the number who could suffer a breakthrough infection and experience a worse outcome due to being vaccinated.  Keep in mind adolescents can have bad outcomes from COVID.  While death is rare, they get “long-haul” infections much as the adult population.  The theoretical risk therefore is expected to be offset by the benefit they are known to receive.

C’mon Doc, What Should I Do?

This is where I get a bit philosophical on you.  We all have a mutual responsibility to one another.  That means taking on some risk now and again on behalf of others.  We are not talking about running across the train tracks to save someone from the oncoming train.  Imagine how our society would function if we didn’t.  I am sure you like your electricity.  For you to have it, there are folks willing to risk their lives.  Most of us never give it consideration, but I know someone who was shocked off one of the lines suffering severe burns doing just that.  Works out great when you accidentally set your house on fire and folks come to put it out rather than letting it burn to the ground?  How about the lifeguard who heads out to try to pull the drowning, thrashing kid out of the ocean at the peril of get pulled under by them?  How about taking a shot that was already given to several hundred million adults without significant concerns and a ton of benefit?

Regarding the question of adolescents and potentially younger children in the future, the answer lies in strategy.  The goal is to eliminate severe disease, including long-haulers.  We started with the elderly and high risk and progressed to vaccinate all willing adults.  It is not sufficient.  We will need to work backwards down the number line.  Next up are our adolescents.  Will we be able to stop there?  Maybe.  Might we be revisiting this with more data on adolescents and initial data on children in a few months.  Quite probably.  This needs to be taken care of before the fall when coronavirus season warms up again.  The more the adults comply, the less we will rely on progressively younger ages in an attempt to reach herd immunity.   Might we never achieve herd immunity?  Sure.  Hopefully if not, we still render the severity of what circulates to something far less significant than the current situation.

Post authored by Jason Halegoua PhD, MD, MBA, FAAP.  Jason is the founder of Peds First Pediatrics in 2009, and has been a practicing general pediatrician since completing residency at Schneider Children’s Hospital in 2004.  In addition to earning his medical degree from the Medical College of Pennsylvania, Jason earned a PhD in Molecular Pathobiology for his work contributing to the understanding of the genetic regulation of immune responses to murine leukemia viruses from Hahnemann University in Philadelphia and an MBA in Finance from Hofstra University.