Dr. Claire Castellano (she/her/hers) is a resident physician in pediatrics at the Children’s Hospital of Philadelphia. In addition to her MD, Claire has a Master’s in Public Health, focusing on global epidemiology. Claire hopes to combine her interests in medical education and global health in her career as a pediatrician. -Rachel Y. Moon, MD, Associate Editor, Digital Media, Pediatrics
The COVID-19 pandemic took the world by storm, creating lasting effects on patient health and the health care system. “Long COVID” or post-acute sequelae of SARS-CoV-2 is one of these effects: a heterogenous array of symptoms, from brain fog to shortness of breath, which significantly impacts certain individuals, seemingly randomly, after infection with COVID-19. There are robust data showing vaccination decreases the risk of acute, severe COVID-19 disease. The data about the impact of vaccination on long COVID in adults are more mixed. However, there is very little research investigating the impact of vaccination on long COVID in children. Hanieh Razzaghi, PhD, MPH, from the Children’s Hospital of Philadelphia, along with colleagues in the RECOVER (Researching COVID to Enhance Recovery) Consortium, investigate this in their paper entitled, “Vaccine Effectiveness Against Long COVID in Children,” being released early in Pediatrics (10.1542/peds.2023-064446).
The authors carried out a retrospective cohort study based on electronic health records, using data from 17 health systems. They identified over 1 million children (5–17 years old) who had an in-person health care visit while they were eligible for a COVID vaccine (between January 1, 2021, and October 29, 2022). More than half (55%) of the cohort received at least 1 vaccination, and of those children, the majority (84%) received 2 or more doses. Participants were followed for 12 months to determine vaccine effectiveness against long COVID.
Given that long COVID is still being understood and not always captured in health records, the authors used 2 strategies to define the condition:
- Diagnosed long COVID: at least two visits with diagnostic codes specific to long COVID
- Probable long COVID: at least two visits with diagnostic codes “compatible with” long COVID (there is a wide range of diagnoses, from “disturbances in taste and smell” to “headache” to “abdominal pain”) OR one diagnostic code specific to long COVID diagnostic code
In this cohort, 0.7% had diagnosed long COVID, and 4.5% had probable long COVID.
Vaccine effectiveness (VE) was calculated to be:
- 7% against diagnosed long COVID
- 4% against probable long COVID
In addition, certain trends emerged:
- VE was higher for adolescents than children (50.3% for 12-17-year-old patients versus 23.8% for 5-11-year-old patients).
- VE waned over time: There was more protective effect early on (61.4% at 6 months), with the protection becoming less as time went on (10.6% at 18 months).
- VE is likely related to protection against the preceding COVID-19 illness because the actual COVID-19 illness after being vaccinated was less severe.
These data suggest that vaccination against COVID is effective in protecting against long COVID in children and adolescents, likely through protecting children from getting any infection or a severe infection. However, the definition of long COVID is broad, leading to possible under-classification and mis-classification. Although the results are encouraging, more research is needed to know if additional or booster vaccinations can help preserve the protective effect against disease and long COVID for children in the future.
