While some countries are pausing administering Moderna vaccines to young people, the U.S. is pushing to start administering Pfizer-BioNTech vaccines to children.

Finland, Sweden and Norway have decided to pause administration of the Moderna vaccine last week due to a link to heart problems. 

Sweden has suspended the use of this vaccine for anyone under 30 years of age, Finland has paused use for men under 30 and in Norway the vaccine is suspended for anyone under 18 years. The countries are offering the Pfizer-BioNTech vaccine to those in these categories instead. Their neighbor, Denmark, has always recommended the Pfizer-BioNTech vaccine for those under 18.

The decision was the result of findings that heart conditions such as myocarditis and pericarditis are possible side effects of the Moderna vaccine. The Norwegian Institute of Public Health reports that these side effects were disproportionately found in young males, and after the second dose.

According to CDC data, “For every 1 million second doses of COVID-19 vaccine, there have been about 67 reported cases in males ages 12-17 years, 56 cases in males ages 18-24 years and 20 cases in males ages 25-29 years… The rates for females were nine, six and three cases, respectively.”

In the U.S., the Moderna and the Johnson & Johnson vaccines are administered only to those 18 and up, while the Pfizer-BioNTech vaccine is administered to those 12 and up. There have been just over 2,000 reported cases of myocarditis as a side effect of the vaccine in the U.S.

Myocarditis is inflammation of the muscle of the heart, and pericarditis is inflammation of the tissue surrounding the heart. 

“The risk of myocarditis is substantially increased for those who contract COVID-19, and vaccination is the best way to protect against this,” said a Moderna spokesperson.

The issue surrounding Covid-19 vaccinations for children in the U.S. is becoming more prevalent and many parents are anxiously waiting for the vaccine to be made available for children under 12. Pfizer-BioNTech and Moderna each ran trials on children back in March, but over the summer, the FDA said they needed to expand on their size in order to detect all possible side effects, including myocarditis and pericarditis.

Pfizer-BioNTech finished these enlarged trials in late September and officially asked the FDA to approve their vaccine for children ages 5-11. The FDA will meet Oct. 26 to discuss and the CDC will meet soon after. 

Moderna has a later time frame, hoping to seek emergency authorization late this year or early next year.

In anticipation of approval of the Pfizer-BioNTech vaccine for children, the Biden administration has purchased $65 million pediatric doses and told governors to prepare to administer the doses next month. The Pfizer-BioNTech vaccine for children is one-third of the dosage for adults, and is administered in two doses.

This will come on the heels of California’s vaccine mandate for schools—the first in the nation. 

The law states that “students will be required to be vaccinated for in person learning starting the term following FDA full approval of the vaccine for their grade span (7-12 and K-6).” Once the vaccine is FDA approved, it will be mandated that children 5-11 be vaccinated to attend school. 

China has been administering vaccines to children three and up since June, using the vaccine from Sinovac, a Chinese biopharmaceutical company. This vaccine has also been approved in Chile for use on children six and up. It is currently being tested for use on children six months to 17 years old in South Africa.

The debate over vaccinating children for Covid-19 has centered around preventing harm. It is unclear what government agencies will do moving forward with regard to vaccine mandates and whether or not they will be allowed for children.