The case to vaccinate kids is , but it's not compelling right now. The Delta variant (B.1.617.2) could change the calculus depending on forthcoming data from the U.K., Singapore, and India where the variant may be demonstrating more contagious and virulent properties in younger people. By now we should all know that it is important to have humility in dealing with this virus. An increase in cases in the U.K. over the last few days is concerning and should be something we follow closely.
Returning to the discussion of the COVID-19 risk to kids (ages 0 to 12 years) right now, it's worth aggregating the best available data to date. In reviewing the medical literature and news reports, and in talking to pediatricians across the country, I am not aware of a single healthy child in the U.S. who has died of COVID-19 to date. To investigate further, my research team at Johns Hopkins partnered with FAIR health to pediatric COVID-19 deaths using approximately half of the nation's health insurance data. We found that 100% of pediatric COVID-19 deaths were in children with a pre-existing condition, solidifying the case to vaccinate any child with a comorbidity.
Given that the risk of a healthy child dying is between zero and infinitesimally rare, it's understandable that many parents are appropriately asking, why vaccinate healthy kids at all?
To those parents, I would say the primary reason to give a healthy child the vaccine may not be to save their life, it's to prevent the multisystem inflammatory syndrome (MIS-C), which can be painful and have long-term health sequelae. According to the CDC, there have been of MIS-C after COVID-19 with the average age being 9 years old. A total of 36 children died. Cases of MIS-C were heavily skewed toward minority children (62% were Hispanic/Latino or Black), likely due to the disproportionate rates of childhood obesity and chronic conditions in these populations. This finding again supports COVID-19 vaccination in any child with a medical condition, including being overweight.
It's also important to note that the COVID-19 exposure risk in children is not linear over time. Since new COVID-19 case rates began , the weekly rate of new cases of MIS-C associated with COVID-19 has . And this week, a on child hospitalizations for COVID-19 in March and April, 2021 found zero deaths in the entire cohort of children studied.
There is an argument for vaccinating children to create a community benefit for kids. Vaccinating healthy kids can help reduce virus transmission to at-risk kids who choose not to get vaccinated or others who cannot get the vaccine. On the other hand, data from Israel suggest that when adult vaccination rates are high, transmission among kids is markedly reduced -- a trend now noted in the U.S. We also know that children are inefficient transmitters of COVID-19 compared to adults. That could potentially change with new information on the recent Delta variant, but so far it hasn't.
The extremely low chance of any benefit for healthy children is exactly why pediatricians like Richard Malley, MD, of Harvard, and Adam Finn, MD, PhD, of the University of Bristol, have to not "use precious coronavirus vaccines on healthy children." A recent in The BMJ echoed this sentiment -- an argument also eloquently articulated by MedPage's own Vinay Prasad, MD, MPH. From a global perspective, two doses of a globally scarce, life-saving vaccine could be more equitably used to immunize a 65-year-old couple in India or Brazil (one dose for each person) rather than giving both doses to one 5-year-old healthy child. Accordingly, California's announcement to spend to pay people to get the vaccine when much of the world is begging for it in the midst of raging epidemics is a sad commentary on our country's excess, inequity, and ethnocentrism.
There may also be unique side effects in children from the second COVID-19 vaccine dose. Seven adolescent children were to have myocarditis within 4 days after receiving the second Pfizer vaccine dose. All were in boys ages 16 to 19. Both mRNA vaccines have been found to be 100% effective in preventing COVID-19 in kids. But anytime a medication is found to be 100% effective, it should call to question whether the dose is too high, the interval is too short, or if there is a need for the second dose at all. Pfizer is now looking at lower vaccine doses for children, as they in their announcement that they are starting their vaccine trial in kids under age 12.
Importantly, and affirmed 2 weeks ago from a Washington University study, immunity is not just conferred by antibodies, it's also a function of memory B and T cells, which the study researchers suggested may confer . Given the near-zero risk of COVID-19 death in healthy children and the recent discovery of rare myocarditis complications immediately after the second dose, this should raise a discussion of whether a single dose is the more appropriate approach for healthy kids.
In my residency training, I was taught an old dictum many of you might be familiar with: "If you give someone blood, always give at least two units." It took decades for the medical community to undo that dogma. We now understand that there are rare but real harms to a second unit of blood. We have matured to recognize that if a second unit is not necessary, one unit is actually safer than two. We should similarly abandon the notion that the vaccine must always be given as two doses. In transplant patients for example, it may be three. In kids with natural immunity from prior infection, it may be none.
What about children who are confirmed to have had COVID-19 infection in the past? I would recommend avoiding COVID-19 vaccination. Looking at natural immunity in adults as a point of comparison, the are overwhelming: natural immunity is real and it works.
Researchers from the Cleveland Clinic published a this week that found "Not one of the 1,359 previously infected subjects who remained unvaccinated had a SARS-CoV-2 infection over the duration of the study." This is one of many studies showing that natural immunity is powerful. While the long-term durability of natural immunity is unknown, it's also unknown for vaccinated immunity. We can postulate with strong rationale, but to be true to the science, we have zero data beyond 18 months for either. In fact, there is more follow-up data on natural immunity than there is on vaccinated immunity. Based on , children who have had COVID-19 should not get vaccinated, unless they are immunocompromised.
One final and minor consideration should be needle anxiety, which has no or minimal effect on most children but can be traumatic for some. For kids who should receive the vaccine and also have needle anxiety, cold therapy and vibrating devices, such as with the , can be applied to the skin injection site prior to injection and result in little to no .
In my opinion, the COVID-19 vaccine makes sense for any child who is overweight or has a pre-existing condition. It also may make sense for a teenager given their closer physiologic similarity to adults and the fact that historically, vaccines safe in adults have been safe in kids when dosed appropriately. But given the case-report level rarity of a healthy child dying of COVID-19, I would not recommend a two-dose vaccine regimen for a healthy child ages 0 to 12 years until we have more data. Each parent will have to assess their own child's individual risk, but in my opinion, the case to vaccinate young healthy kids is not compelling right now.
Marty Makary, MD, MPH, is Editor-in-Chief of 番茄社区 and a professor at the Johns Hopkins School of Medicine, Bloomberg School of Public Health, and Carey Business School. He is author of .