Fall is approaching, which means it's time to start thinking about flu vaccines. And parents of toddlers might be wondering whether it matters if their kids receive the injected or nasal-spray vaccine. Is the nasal spray okay for toddlers? Is the extra crying from a shot worth it?
The two vaccines had similar effects in a group of 53 kids aged 6 months to 3 years, a new study released today by the National Institutes of Health concludes. Children in the study received two doses of seasonal influenza vaccine, as is standard for children who have never been vaccinated before. Some kids got only the injected vaccine, others only the nasal spray, and some got one dose of each type of vaccine.
Both vaccines were safe in toddlers and gave them similar levels of protective antibodies. It wasn't a problem to mix vaccine types, either - one dose of each type of vaccine worked just fine, regardless of which was given first.
But getting at least one dose of nasal spray vaccine, which contains a live attenuated virus, gave kids an extra advantage, revving up the immune system's T cells:
When the investigators looked at responses from the T-cell arm of the immune system, a striking difference emerged. They could not detect influenza-specific T cells in children who received only TIV [injected vaccine], according to Dr. Hoft. But, he added, "The kids who received at least one dose of LAIV nasal spray vaccine produced significant amounts of three important T-cell subtypes that are likely to confer additional protection beyond that afforded by antibodies alone."
The researchers note that the nasal spray sometimes caused wheezing in the smallest children, so they suggest that one dose of the injected vaccine followed later by a dose of the nasal spray might be the best vaccination strategy, though the results need to be repeated in larger studies.