ASOURCE Navi

Globally, there is no clear consensus on vaccination against COVID-19 for children in their early teens, and the response to COVID-19 vaccination for children differs from country to country.

In Japan, two doses of the corona vaccine are administered to children aged 12 to 15, but the vaccination rate for children aged 12 to 19 is about 67% for the first dose and about 48% for the second dose (October 25th). Overseas, in France (12-17 years old), 66% for the first time, 52% for the second time. Most children in Denmark (ages 12-15) and Spain (ages 12-19) receive the first dose (as of September). In the United States (12-17 years old), 42% for the first time and 32% for the second time (as of the end of July).

There are three types of new corona vaccines used in Japan, but children over the age of 12 can get the mRNA vaccine made by Pfizer or Moderna. On October 15, the Ministry of Health, Labor and Welfare warned that men in their teens and twenties have a relatively high rate of symptoms of myocarditis and pericarditis after being vaccinated with Moderna. We also decided to allow people who inoculated with Moderna to choose Pfizer for the second time. Inflammation of the heart muscle is called myocarditis, and inflammation of the membrane surrounding the heart is called pericarditis. Symptoms include chest pain, shortness of breath, and palpitations. For males aged 12 to 19, the incidence of myocarditis and pericardiopathy per 1 million people vaccinated is 28.8 for Moderna, which is 7.8 times higher than 3.7 for Pfizer. For this reason, overseas, on October 6th, Sweden announced a temporary suspension of Moderna vaccination for those under 30 years old and Denmark for those under 18 years old.

Meanwhile, the UK has recommended that only one vaccination be given to 12- to 15-year-olds in September this year, and that the second vaccination be postponed until next spring at the earliest until more detailed data are available. The reason is that children are at such a low risk of contracting the virus that they see little benefit from vaccination. The decision was made out of concern that the Pfizer and Moderna vaccines have extremely rare side effects such as myocarditis and pericarditis.

However, most cases of myocarditis and pericarditis after vaccination are mild cases and are said to resolve spontaneously. It has also been reported that post-vaccine myocarditis/pericarditis is less frequent than the incidence of myocarditis/pericarditis after infection with COVID-19.

Regarding the side effects of the corona vaccine for 12 to 15 year olds, the results of a clinical trial in which Pfizer vaccine was administered to 1,131 people aged 12 to 15 years old, including Asians, have been reported by a clinical trial group in the United States. (The New England Journal of Medicine: July 15, 2021). Fever of 38°C or higher was observed in 20% after the second dose (10% after the first dose). On the day after administration, one patient had a fever of 40°C or higher. Antipyretics were used in 51% (37% of the previous year), and most of the patients recovered with antipyretic treatment and were cured within a few days. Injection site pain was observed in 79% (86% of the previous year), but only 1.5% complained of severe pain. As for the breakdown of other adverse reactions after administration, malaise 66% (60% after 1st dose) and headache 65% (55%) were common after the 2nd dose, followed by chills 42% (28%). Myalgia was 32% (24%), arthralgia 16% (10%), diarrhea 6% (8%), vomiting 3% (3%).

As for vaccinating children of other ages, on October 26, an advisory panel to the U.S. Food and Drug Administration (FDA) made a recommendation to extend the emergency use authorization for Pfizer vaccines to ages 5 to 11. Approximately 91% of the dose for adults was confirmed to be 91% effective, and there were no serious side effects from vaccination. If the FDA allows it, vaccination will start as early as November. On the other hand, Moderna confirmed that in clinical trials of the company's vaccine for 6 to 11 years old, the antibody increased 1.5 times that of adults at half the dose of adults, and most side reactions were mild or moderate. The company plans to submit data to the FDA and other national regulatory agencies in the near future.

Regarding vaccination for healthy children, the Japan Pediatric Society states, ``It is premised that the child and their caregivers fully understand the advantages and disadvantages of vaccination, and that careful attention is given before, during, and after vaccination. It is.