ELS and SARS-CoV-2 vaccines
With SARS-CoV-2 vaccines now authorized for adolescents and expected in a few months for younger children, large local AEFI reactions related to pediatric SARS-CoV-2 vaccines are expected, given that “COVID arm” is now well described in adults.4 Overall, ELS/large local reactions have been reported more frequently with the Moderna than Pfizer mRNA vaccine.4 In the almost 42% of adults having ELS post first dose, repeat ELS post second dose often appears sooner but also resolves more quickly, with no known sequelae.5
Dr. Christopher J. Harrison
Some biopsies have shown delayed-type hypersensitivity reactions (DTH) (superficial perivascular and perifollicular lymphocytic infiltrates with rare eosinophils and scattered mast cells),6,7 while others show no DTH but these patients have findings of immediate hypersensitivity findings and negative skin testing to the vaccine.8 With regard to sex, Dutch ELS data in White adults reveal 90% occur in females – higher than the 75% female rate after standard vaccines.7 Onset of ELS data show that Pfizer mRNA vaccinees had onset on average at 38 hours (range, <1 hr to 12 days). Boston data mostly in White adults reveal later onset (median, 6 days; range, 2-12 days).4 In contrast, adults of color appear to have later onset (mean, 8 days; range, 4-14 days).9
In addition to the local swelling, patients had concurrent injection-site AEFIs of pain (65%), warmth (63%), and pruritus (26%), plus myalgia (51%), headache (48%), malaise (45%), fatigue (43%), chills (33%), arthralgia (30%), and fever (28%).7
What should we tell families about pediatric ELS before we give SARS-CoV-2 vaccines to children? Clinical pediatric SARS-CoV-2 vaccine trials are smaller “immunologic bridging” studies, not requiring proof of efficacy. So, the precise incidence of pediatric ELS (adult rate is estimated under 1/100,000) may not be known until months after general use. Nevertheless, part of our counseling of families will need to include ELS/large local reactions. Unless new data show otherwise, the spiel that clinicians have developed to counsel about the rare chance of ELS after routine vaccines should also be useful to inform families of the rare chance of ELS post SARS-CoV-2 vaccine.
The bottom line is that the management of pediatric ELS after SARS-CoV-2 vaccines should be the same as after standard vaccines. And remember, whether the reactions are DTH or not, neither immediate local injection-site reactions nor DTH reactions are contraindications to subsequent vaccination unless anaphylaxis or Arthus reaction is suspected.10,11
Dr. Harrison is professor of pediatrics and pediatric infectious diseases at Children’s Mercy Hospitals and Clinics, Kansas City, Mo. He said he had no relevant financial disclosures. Email him at pdnews@mdedge.com.
References
1. Woo EJ and the Vaccine Adverse Event Reporting System Working Group. Clin Infect Dis 2003;37:351-8.
2. Rennels MB et al. Pediatrics 2000;105:e12.
3. Huber BM, Goetschel P. J Pediatr. 2011;158:1033.
4. Blumenthal KG et al. N Engl J Med. 2021;384:1273-7.
5. McMahon DE et al. J Amer Acad Dermatol. 2021;85(1):46-55. 6. Johnston MS et al. JAMA Dermatol. 2021;157(6):716-20 .
7. ELS associated with the administration of Comirnaty®. WHO database Vigilyze (cited 2021 Feb 22). Available from https://vigilyze.who-umc.org/.
8. Baeck M et al. N Engl J Med. 2021 Jun. doi: 10.1056/NEJMc2104751.
9. Samarakoon U et al. N Eng J Med. 2021 Jun 9. doi: 10.1056/NEJMc2108620.
10. Kelso JM et al. J Allergy Clin Immunol. 2012;130:25-43.
11. Zafack JG et al. Pediatrics. 2017;140(3):e20163707.