Measles. Mumps. Rubella. Diptheria. Polio. Whooping Cough. These are childhood diseases that are no longer terrifying, thanks to vaccines.
Soon there will be a new addition to the list: COVID-19.
On Wednesday, Pfizer launched its test of a childhood vaccine in a pair of 9-year-old twin girls at Duke University in North Carolina. Stanford University will also participate in that trial, which will assess the vaccine in children between the ages of six months to 11 years. Studies are already underway of both the Pfizer and Moderna vaccines in adolescents ages 12 years to 15 years.
By late April or early May, scientists expect to get initial results of vaccine tests in adolescents. It’ll be later – the second half of the year, according to Pfizer – to obtain data in younger children.
“We want to protect our children,” said Stanford pediatrician and infectious disease expert Dr. Yvonne Maldonado, who will lead Stanford’s trial of the Pfizer vaccine in children later this spring.
“And we want to protect the general population,” she added. With children representing more than one-fifth of U.S. residents, “if you can vaccinate at least even a good proportion of kids, that will prevent transmission.”
Will the vaccines get the go-ahead in time for the next school year? That’s not known. While the federal authorization process will be shorter than it was for adult vaccines, manufacturers must still prove safety and efficacy.
Although relatively few children sicken and die of COVID-19, it is not a benign illness, according to the American Academy of Pediatrics and the Centers for Disease Control and Prevention.
An estimated 270 children have been killed by the virus, shattering families. Thousands more have been hospitalized; of these, some suffer from lingering effects, such as heart problems. Victims are disproportionately children of color and persons with underlying medical conditions.
Federal experts said it was important to wait and learn from the adult vaccination experience before inoculating children.
Now, with more than 100 million doses of vaccines now delivered into the arms of American adults, safety has been established.
At Duke, one of four study sites in the U.S. for the initial Pfizer trial, Alejandra and Marisol Gerardo received their first dose of the two-dose vaccine. Their father, Dr. Charles Gerardo, is chief of emergency medicine at the university’s School of Medicine. This first phase of the study, designed to evaluate three different dosage levels, is only enrolling 48 children. The later phase, which will include Stanford, will enroll up to 4,500 children.
The Pfizer vaccine is already authorized for people ages 16 and older. For example, teens with chronic health conditions, such as morbid obesity or immunosuppression, are getting shots at UCSF Benioff Children’s Hospital in Oakland, said Dr. Dayna Long, co-director of the hospital’s Center for Child and Community Health.
For younger and healthier youth, all top four vaccine manufacturers have trials planned or underway:
• Pfizer will test its vaccine in separate cohorts of patients between the ages 16 and 12 years, 12 and 5 years, 5 to 2 years and 2 years to 6 months. In Oakland, Kaiser Permanente Vaccine Study Center has already tested the Pfizer vaccine in healthy youth ages 12 and older.
• Moderna is now testing its vaccine in children ages 12 to 17 years. Two weeks ago, Moderna announced it would start a trial in children ages 6 months to 11 years.
• Johnson & Johnson plans to test its vaccine in people ages 12 to 18, later testing children under age 12.
• Astra Zeneca started testing its vaccine in February in youth between the ages of 6 to 17.
Merck, the nation’s largest maker of childhood vaccines, does not have a COVID-19 vaccine. But, in general, the pharmaceutical industry has a long track record in building safe vaccines for children, said pediatrician Dr. George Rutherford, an infectious disease expert at UC San Francisco.
With extensive experience in adults, “this is a pretty straightforward exercise for them to move from adolescent trials to pediatric trials,” he said.
But these youth studies will differ from the adult trials in two major respects, said Rutherford and Maldonado.
First, researchers won’t wait for children to get sick or die to determine a vaccine’s efficacy. Because infected children are far less likely to develop illness than adults, such a strategy would take years and require tens of thousands of volunteers. Instead, they will look at youngsters’ blood. The presence of abundant antibodies, rather than illness or death, will prove that a vaccine works, said Rutherford and Maldonado.
Secondly, researchers will test different dosage levels to identify how much vaccine is needed to trigger the greatest response with the fewest side effects, they said. A six-month-old infant needs a much lower dose than a grown man, for instance. So the trials are structured in phases, starting with low doses. Pfizer says it will initially test three doses — 10, 20 and 30 micrograms — in children ages 5 through 11.
Bay Area parents say they would welcome the chance to participate, with some caveats.
“We would definitely welcome, support, and participate in a pediatric COVID-19 vaccine trial, because we understand and believe in the science, and the need to have trials to support proper medical conclusions,” said Jonathan Luk of Los Altos, whose children are ages 14, 16, and 19.
Jessica Shambora, also of Los Altos, said “I’d be comfortable having our older son, who is almost age five, participate in a trial — but not the baby, who is not yet six months old. It just feels too risky for an infant.”
If clinical trials prove the vaccines to be safe and effective, Los Gatos resident and community college educator Lesley Louden said she’d vaccinate her children, ages 6 and 7, for three reasons: “to protect them from getting sick and dying from COVID-19, to protect them from COVID-19 related health issues if they were to be infected, and because some teachers are not choosing to be vaccinated.”
“I have been safely vaccinated with the Pfizer vaccine with no side-effects — and I felt so much relief,” she said. “The next layer of relief will be when my husband and children are also safely vaccinated.”