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Wide World of Vaccines

October 2021

5- to 11-year-olds Soon Eligible for COVID-19 Vaccine, Plus Vaccine Factoids


 Christopher Harrison, MD

Column Editor: Christopher Harrison, MD | Professor of Pediatrics, UMKC School of Medicine | Clinical Professor of Pediatrics, University of Kansas School of Medicine


The emergency use authorization (EUA) approval of SARS-CoV-2 vaccines for 5- to 11-year-olds is taking a bit longer than we hoped. For the Pfizer vaccine it will likely occur just before or after Halloween with the Moderna vaccine hopefully sometime in December.

Some primary care practitioners administer these vaccines since the storage temperature requirements have loosened, and some prefer referring their patients to large centers, pharmacies or vaccination sites. A good resource to find a vaccination site is This site has data by vaccine manufacturer and permits searches within a given zip code. Families can alternatively text their ZIP code to 438829 (GETVAX) or call 1 (800) 232-0233 for information.

Nevertheless, let’s quickly review existing data for the vaccine in 12- to 17-year-olds, vaccine differences for 5- to11-year-olds vs. older individuals, and some new information that pertains to families’ potential vaccine reluctance.

Current SARS-CoV-2 pediatric vaccine uptake: For 12 through 17-year-olds, the uptake rate is 56% for one dose and 46% for two doses as of Oct. 6, 2021.1 Weekly pediatric vaccine uptake peaked in May (1.6 million) and then dropped with a modest second peak (586,000) in August just as schools reopened. (See 10/6/21 AAP analysis of CDC data here, page 6.) But like adults, rates vary wildly between states, with West Virginia, Wyoming, South Dakota and a handful of southeast states being <40%, while five northeast states plus the District of Columbia and New Mexico being >70% vaccinated. (See 10/6/21 AAP Analysis of CDC Data here, page 9). Adverse effects (AEs) in these adolescents (pain at the injection site, tiredness, headache, chills, muscle pain, fever and joint pain) were transient (one to three days) and at similar frequency as in older vaccinees.

Myocarditis: The AE that has caused a longer review of data for 5- to 11-year-olds and that may concern families the most is the rare AE of myocarditis post-vaccine. Yet the ACIP and AAP currently recommend vaccination in 12- through 17-year-olds due to favorable risk-benefit for the vaccine. These myocarditis episodes in pediatric patients to date occur at approximately two days post either first or second vaccine dose and predominantly in males but have been mostly mild and have had full recoveries. The myocarditis rate among SARS-CoV-2 infected 12- to 17-year-olds has been reported to be over 12 times as high as the rate post vaccine (62.8 vs. <5 per million, respectively)2,3 and infection-related myocarditis was more often associated with ICU stays.

Since preteen children are now among the groups with the highest rates of infection and we expect all children who remain unvaccinated to get infected by Summer 2022, we also expect the same vaccine recommendation for 5- to 11-year-olds. Of course, this depends on whether the FDA agrees with Pfizer’s conclusion that the 5- to 11-year-old’s 10 mcg dose vaccine safety profile is the same as or better than the 30 mcg dose for older children.

Vaccine differences:

  1. For 5- to 11-year-olds, the Pfizer vaccine dose will be 10 mcg vs. 30 mcg for 12- to 17-year-olds. Note: pending lawsuits have been based on the 30 mcg dose being given to children under 12 years of age.
  2. The vaccine for 5- to 11-year-olds will come in an ORANGE cap vial vs. the PURPLE cap vial for older children.
  3. New CPT codes for 5 through 11 years of age: 91307, 0071A, and 0072A. The codes were published on Oct. 6, 2021, and will be valid as soon as EUA is granted.

Vaccine similarities:

  1. Both come in multidose vials.
  2. Long-term storage up to six months is in ultra-cold freezers but the vaccine is stable up to 10 weeks in a refrigerator.
  3. The schedule is two doses administered three weeks apart.

Vaccine Factoids:

  1. Vaccination of health care workers (HCW) reduced intrafamilial transmission. In a recent UK report, researchers compared COVID-19 acquisition within 92,470 HCW households with two to 14 persons per household, using an unvaccinated period pre-dose 1 as the baseline. They compared infections in the 14 days post HCW dose 1 and in 14 days post HCW dose 2.4 Infection rates/100 person-years within households was 9.40 before dose 1, dropping to 5.93 post dose 1 and to 2.98 post dose 2. The hazard ratios for infection were 0.7 (95% CI , 0.63-0.78) and 0.46 (0.30-0.70), respectively. In other words, two HCW doses decreased the chance of household members getting infected by 54%.
  2. Menstrual changes post COVID-19 vaccines. Nearly 30,000 temporary menstrual changes or unexpected vaginal bleeding episodes after vaccination have been reported to the UK equivalent of VAERS,5 but appear to return to normal at the expected time of the next cycle. So there seems to be a potential link to temporary cycle changes but causality has yet to be confirmed. If families raise this issue, we can reassure them that things should return to normal rather quickly. This report also reviewed data indicating that, despite a potential one- to two-month change in menstrual cycles, the vaccine does not affect fertility.
    1. In clinical trials, unintended pregnancies occurred at similar rates in COVID-19 vaccinated and unvaccinated groups.6
    2. In assisted reproduction clinics, fertility measures and pregnancy rates are similar in COVID-19 vaccinated and unvaccinated patients.7,8,9,10
    3. These data can be reassuring when we counsel concerned families about infertility.
  3. Vaccine costs to the health care system. Among the various COVID-19 vaccines, U.S. costs average about $30/dose. These costs would have been higher if the government had not subsidized vaccine development and negotiated prepaid deals. This is such a bargain, particularly when compared to the cost of monoclonal antibody cocktail treatments that average approximately $2,000 per dose. And the monoclonal antibodies likely only protect for one to two months. So, the vaccine is a fiscally, as well as socially, responsible option.

Have a happy and safe Halloween – mostly outside, I hope.



  1. Summary of data publicly reported by the Centers for Disease Control and Prevention Date: 10/06/21.
  2. Tegan K. Boehmer, et al. Association between COVID-19 and myocarditis using hospital-based administrative data — United States, March 2020–January 2021. MMWR. Early Release / Vol. 70 August 31, 2021, pp.1-6.
  3. Wallace M, Oliver S. COVID-19 mRNA vaccines in adolescents and young adults: Benefit-risk discussion.
  4. Anoop SV Shah, et al. Effect of vaccination on transmission of SARS-CoV-2. The New England Journal of Medicine. Downloaded from on Sept. 16, 2021. DOI: 10.1056/NEJMc2106757.
  5. Menstrual changes after COVID-19 vaccination. A link is plausible and should be investigated. BMJ 2021;374:n2211
  6. Male V. Are COVID-19 vaccines safe in pregnancy? Nat Rev Immunol 2021;21:200-1.
  7. Morris RS. SARS-CoV-2 spike protein seropositivity from vaccination or infection does not cause sterility. F S Rep 2021. doi: 10.1016/j.xfre.2021.05.010. pmid: 34095871.
  8. Orvieto R, et al. Does mRNA SARS-CoV-2 vaccine influence patients’ performance during IVF-ET cycle? Reprod Biol Endocrinol 2021;19:69.
  9. Bentov Y, et al. Ovarian follicular function is not altered by SARS-Cov-2 infection or BNT162b2 mRNA COVID-19 vaccination. medRxiv 2021:2021.04.09.21255195. [Preprint].
  10. Safrai M, et al. Stopping the misinformation: BNT162b2 COVID-19 vaccine has no negative effect on women’s fertility. medRxiv 2021:2021.05.30.21258079 [Preprint].