Published online in Pediatrics on Tuesday, September 25, 2018
Two kinds of vaccine, one that promotes the immune system’s natural process of protection and another that works to eliminate infectious agents, are often given together as boosters to minimize the chance of the second one causing a harmful reaction.
Now, in a study published Tuesday in Pediatrics, researchers have shown that one vaccine and one booster combination provide relatively strong immune protection against an invasive disease, a contrast with a 2010 study that raised concerns about children’s health outcomes after receiving the full dose of a flu vaccine.
The new study involved all the children who had received the flu vaccine this season, which started on Nov. 15, 2016. It tracked all the children for a year and compared the numbers of cases that were confirmed by pathologists for those who had received one vaccine (the chicken pox vaccine) and a separate booster (the type 1 diabetes vaccine) to those diagnosed with mumps among those who had not.
The children whose vaccines combined were tested had lower rates of a type of rash, called “conjunctivitis,” which had previously been thought to occur when the immune system’s immune response to the second vaccine was too strong. But what the study really found is that children received a higher number of vaccine doses than previous studies suggested – about 11.5 doses, compared with about eight. And they appeared to get stronger protection than people receiving just one, which adds to the already serious problems the CDC is seeing with that dosage.
“Our latest study is another evidence-based document that vaccines with two vaccines in a booster package are as effective as the single vaccine,” said lead author Dr. Ankit Latoria, who teaches at the University of Washington. His team had previous study findings suggesting that the two types of vaccines could work together to offset each other’s weaker immune responses to an invading pathogen.
It is still uncertain how different the vaccine’s immune response will be to viral illness over the year, Latoria said.
“This is how immune response changes over the course of the whole year and affects the immune system,” he said. “It’s hard to predict how the immune system will respond to each course of a viral infection.”
The results do not mean children should no longer be vaccinated against mumps, since these combinations work against an infection that is still prevalent, Latoria said.
The American Academy of Pediatrics recommends immunizing 9-17 year olds against chicken pox and type 1 diabetes. Certain groups should receive vaccinations separately, such as children with underlying medical conditions or women who are pregnant. However, immunizations include a second vaccine, which can make them more beneficial against some infections, such as pertussis, sometimes called whooping cough. That vaccine is more effective than others at protecting against this disease, and would be the one they are considered more likely to have received.