If you’ve been following The Pulse Blog for the last few years, you know that we have posted many articles about COVID-19 infection and vaccines during pregnancy and childhood. For this reason, we wanted to let you know about a new development in the effort to provide COVID-19 vaccines for every age group.
Moderna is recruiting infants for a clinical trial, called BabyCOVE, of its investigational vaccine in infants between the ages of 12 weeks and less than 26 weeks (6 months). This is the same type of vaccine that adults and older children receive from Moderna, but administered in lower doses as part of the ongoing Phase 2 study.
The Moderna mRNA vaccine is currently authorized for use with adults and children ages 6 months and up. There has been some concern about the potential development of inflammation of the heart in teenage boys, after receipt of the vaccine (given the same dosage that adults receive). For Moderna, this means the dosage is 100 micrograms for each of the two injections of the two-shot primary series. Such heart inflammation is rare, and such cases are typically subclinical. This means that certain medical tests – blood tests for proteins that leak from heart muscle when it is stressed and advanced imaging scans of the heart – reveal an inflammatory process without symptoms occurring. Compared with the risk of severe disease developing in teens infected with SARS-CoV-2 (the virus that causes COVID-19), even though that risk is much lower compared with adults, vaccination is still recommended for teenage boys by the U.S. Centers for Disease Control and Prevention (CDC).
The dosage of mRNA vaccine for children under 12 years old is less than what adults receive, and there has been no observation of heart inflammation in the under-12 age groups from the vaccine (CDC). A small percentage of children who became ill with COVID-19 developed a complication called Multisystem Inflammatory Syndrome in Children (MIS-C) a few weeks after recovering from the COVID-19 infection. One complication of MIS-C can include heart inflammation. Rare cases of severe MIS-C (which can lead to death) can occur. Cases of severe MIS-C have been more common within the 5- to 13- year age group. For this reason, the CDC recommends that everyone age 6 months and up be vaccinated.
Currently, Moderna is recruiting participants for a Phase 2 clinical trial to study a version of its mRNA-1273 vaccine at a dose that has been developed for infants. Infants between the ages of 12 weeks and less than 26 weeks will be enrolled, and two different dosages of the vaccine will be tested. Each participant will be given series of two injections. Infants as young as 8 weeks will be able to be screened, to begin dosing when they reach at least 12 weeks of age.
Now, we did note that development of MIS-C is possible after infection and recovery from COVID-19, which strikes mostly in school age children, those ages 5-13. So, what then is the rationale for testing an infant vaccine? For that perspective, it can be useful to be aware of the numbers for hospitalizations in this age group. It’s true that the overwhelming number of COVID-19 deaths in the US have occurred among older people. Children account for approximately 1 out of 5 cases of COVID-19 infection. Older children account for more COVID-19 cases requiring hospitalization and for more deaths compared with younger children. However, infants below the age of six months actually account for more cases of hospitalized COVID-19 than children in the age group of six months to four years. At this point, several hundred children have died of COVID-19 in the United States, and of that total, infants below the age of 6 months comprise a significant fraction. As noted, the vaccine doses being tested in this Moderna Phase 2 trial are developed for infants, and Moderna says that safety is very much their top priority. The question is whether 5 mcg or 10 mcg, given in two injections is going to be enough to be effective. Answering this question requires testing on infants, and if it does prove effective, your infant could be among the first to benefit from such protection.