School-related Covid-19 clusters have increased substantially in Malaysia since the opening of the school, especially with the most recent Omicron surge. Most children who are infected stay asymptomatic, but they may easily transmit the virus to others, including those who are at higher risk of severe diseases. According to CovidNow, children aged 5 to 11 had made up about 10 per cent of the country’s total Covid-19 cases in recent weeks, and it is predicted that the incidence for younger children is likely to increase further.
Following the vaccination drives for adults and adolescents, Malaysia has started to roll out COVID 19 vaccination programme for children. Many countries like United States, Canada, Germany, Austria, Belgium, Hungary, Greece, Singapore, and Indonesia have started vaccination for children aged 5 to 11 in late 2021.
Many parents in Malaysia are concerned about the safety profile of the Pfizer-BioNTech vaccine for younger children and following are findings of studies on the efficacy and safety of the vaccine for this age group.
In preauthorisation clinical trials as reported by CDC USA, Pfizer-BioNTech COVID-19 vaccine was administered to 3,109 children aged 5–11 years; most adverse events were mild to moderate, and no serious adverse events related to vaccination were reported. CDC reviewed adverse events after receipt of Pfizer-BioNTech COVID-19 vaccine reported to the Vaccine Adverse Event Reporting System (VAERS), during November 3–December 19, 2021. Approximately 8.7 million doses of this vaccine were administered to children aged 5–11 years old during this period; VAERS received 4,249 reports of adverse events after vaccination in this age group, and 97.6% of which were not serious (1).
There has also been some concern over cases of myocarditis and pericarditis following the administration of mRNA vaccines. Myocarditis is a rare but serious adverse event that has been associated with mRNA-based COVID-19 vaccines; reporting rates for vaccine-associated myocarditis appears highest among males aged 12–29 years. To date, myocarditis among children aged 5–11 years appears very rare with approximately 11 cases in 8.7 million (2).
Myocarditis is well-described long before the COVID-19 pandemic. It can occur when a virus, such as the common cold, influenza (flu) or indeed the SARS-CoV-2 (the virus that causes COVID-19) infects the body. Fortunately, current studies show that post-vaccine-related myocarditis is typically much milder than classic myocarditis due to the viral infection, with symptoms lasting for a shorter amount of time and usually resolving with minimal, if any, medical treatment.
In two recently published randomised controlled trials on Pfizer-BioNTech vaccine for children and adolescents, the investigators reported that the vaccine achieved over 90% reduction in the risk of contracting COVID 19 for children 5 to 11 years old as well as adolescents, with no serious adverse events such as myocarditis observed in the period of the study (2, 3). However, as with adults, mild reactions such as injection site pain, fatigue and headache were reported. Parents and guardians of children aged 5–11 years vaccinated with Pfizer-BioNTech COVID-19 vaccine should be informed of the possibility of such reaction after vaccination, probably more likely after the second dose. The parents should also advise the child to avoid strenuous exercise two days before and up to two weeks after vaccination.
Some parents are considering opting out of vaccinating their children in hopes of depending on herd immunity. Traditionally, herd immunity is achieved when 80% of the population have been fully immunised against an infection. But this is not so with COVID 19, especially with the new Omicron variants, the estimates are much higher. We will likely need more than 95% of the population fully immunised to achieve a degree of protection similar to that conferred by herd immunity (4). Currently, our population immunised stands at 79%.
Herd immunity is also a dynamic phenomenon that depends on the movement of the herd. Let’s say if a family has five adults and one child, and all adults are immunized, then one can say that the family has herd immunity—provided that the family live in the same house all the time, and the child never spends any time outside.
If the child goes to school, the majority of the population are children. If all children who are not immunised congregate there, there is no herd immunity in that setting. The danger of depending on herd immunity is if most parents decide to not immunise their children, then it’s certain that there won’t be just a few selected few who opt not to be immunised, and this will spell big trouble for the general level of immunity among children.
The current phenomena of an apparently milder course of illness when one contracts the Omicron variant is the result of having our immunity propped up by vaccination. The illness will certainly be more serious across the population if we are not vaccinated. Some believe we should now be treating Omicron like normal flu, but we would advise not to let down our guards just yet.
Vaccination is still the most effective way to prevent COVID-19 infection and the development of serious complications, including the likelihood of reduced transmission in the home and in school settings, to safeguard vulnerable persons, and create a safer in-person learning environment.
Without effective Covid-19 vaccines for this age group, children could potentially become ongoing reservoirs of infection and sources of newly emerging variants. Widespread vaccination across age groups is therefore essential in ongoing efforts to curtail the pandemic.
In the nutshell, children aged 5 to 11 years old are encouraged to be vaccinated against Covid-19 virus. Nevertheless, if the child has any pre-existing medical condition or any parents who are in doubt should seek advice from their general medical practitioner or paediatricians.
References
(1) Hause AM BJ, Marquez P, et al. COVID-19 Vaccine Safety in Children Aged 5–11 Years— United States, November 3–December 19, 2021. MMWR Morb Mortal Wkly Rep. 2021;70:1755–60.
(2)JR S. COVID-19 vaccine safety updates:Primary series in children and adolescents ages 5–11 and 12–15 years, and booster doses in adolescents ages 16–24 years. Advisory Committee on Immunization Practices, January 5, 2022 [Internet]. 2022. Available from: https://www.cdc.gov/vaccines/acip/meetings/downloads/slides-2022-01-05/02-covid-su-508.pdf.
(3)Frenck RW, Jr., Klein NP, Kitchin N, Gurtman A, Absalon J, Lockhart S, et al. Safety, Immunogenicity, and Efficacy of the BNT162b2 Covid-19 Vaccine in Adolescents. The New England journal of medicine. 2021;385(3):239-50.
(4)Walter EB, Talaat KR, Sabharwal C, Gurtman A, Lockhart S, Paulsen GC, et al. Evaluation of the BNT162b2 Covid-19 Vaccine in Children 5 to 11 Years of Age. 2021;386(1):35-46.
(5)Omer SB, Yildirim I, Forman HP. Herd Immunity and Implications for SARS-CoV-2 Control. JAMA. 2020;324(20):2095–2096. doi:10.1001/jama.2020.20892
Dr Lim Yin Sear,
Senior Lecturer,
Taylor’s University School of Medicine
Dr. Noor Hafiza binti Noordin,
Head of Paediatrics Department,
Hospital Banting
