Late last week, in the United States, the FDA announced that Pfizer-BioNTech’s COVID-19 vaccine (now called Comirnaty), is now authorized for emergency use in children ages 5-11 years old. The FDA’s announcement came after their expert panel’s unanimous decision for approval, based on the findings that the potential benefits of the children’s formulation – 10 micrograms, which is 1/3rd the dose of the 30 microgram adult formulation – largely outweigh the risks for side effects, including the rare heart complication (myocarditis or pericarditis; i.e., inflammation in or around the heart) that has been reported in some teens and young adults who received the higher, standard dosage. The mRNA in the new children’s version of the vaccine is the same as the mRNA found in the adult version, and it works the same way. For an overview of mRNA vaccines, see my newsletter article from February, entitled What the heck is an RNA vaccine?.
Before the vaccine goes into full circulation in the United States (which could be as early as this week), there is one more regulatory hurdle – the Centers for Disease Control and Prevention (CDC) will provide more detailed recommendations on Tuesday, with final approval from the agency following shortly afterwards. One question that the CDC is expected to address is whether all youngsters will need to be vaccinated, or whether the shots should be targeted to those at higher risk from the virus. For example, nearly 70% of 5-11 year-olds hospitalized for COVID-19 in the United States were found to have had other serious medical conditions, such as asthma and obesity.
In the Pfizer trial, the vaccine was studied in approximately 3,100 children ages 5-11, and was found to have an efficacy of 91% against symptomatic infection. There were also relatively few and minor side effects, such as sore arms, fever or achiness. While the Pfizer trial showed that the smaller child-dose proved to be safe and effective, with similar or fewer side effects compared to those that teens experience, the study was not large enough to detect extremely rare side-effects, such as the heart complications that were observed mostly in men and teen boys after their second full-dose. It is unclear if younger children getting the smaller dose will also face that rare risk.
Health Canada received the data from Pfizer’s trial a little later than the FDA. They are still looking at the data, and say that approval could still take four to six weeks. After Health Canada Approval, the National Advisory Committee on Immunization (NACI) will weigh in, and may recommend a longer gap between shots. The Two-dose regimen used in the Pfizer trial had shots administered three weeks apart, but with evidence now that a longer time between doses produced a better immune response in adults, the NACI could recommend a gap of up to 12 weeks between doses, as they did for the adult version.
Once a final decision has been made, it seems likely that in Canada, supply should not be too much of an issue – Prime Minister Justin Trudeau recently announced that soon after approval, Pfizer will supply 2.9 million doses, enough for every Canadian child in this age group to get their first shot.
Moderna will also soon be submitting an application for approval of their pediatric vaccine based on their interim data that shows that for kids ages 6-11, the vaccine shows a strong safety profile and a strong immune response. Moderna’s vaccine for kids is 50 micrograms – half the dose of the Moderna shots authorized for adults – and two doses are administered 28 days apart. In 4,753 children aged 6-11, the most common side effects were fatigue, headache, fever and pain at the site of injection.
Interestingly, back in June, Moderna submitted their study results on approximately 2,500 adolescents aged 12-15 to the FDA, but the agency still has yet to issue a decision on whether to expand the use of the Moderna vaccine in that age group. Pfizer’s vaccine was approved for adolescents aged 12-15 back in May.
Both Pfizer and Moderna are also studying their COVID-19 vaccines in even younger populations – babies and preschoolers. Moderna has already enrolled 5,700 pediatric participants in the U.S. and Canada, and they are continuing to enroll children ages 6 months to 5 years of age.
Since children are less likely than adults to get seriously ill from COVID-19, many parents are questioning why they need to get their kids vaccinated. Unfortunately, some kids do suffer serious illness after contracting the virus with over 8000 hospitalizations and over 145 deaths reported in the US in those aged 5-11. Even if they don’t get sick, children can transmit the virus to those that are more vulnerable. Many public health experts have expressed that it would be ideal if kids can get their first dose before the Christmas holiday season as this could help reduce the spread of the virus during a time when people gather. By vaccinating your children, you are not only protecting them, but you are also protecting your family, including grandparents and elders. The next few months will be interesting and hopefully a big step towards getting closer to returning to a sense of normalcy.