Researchers found that children ages 6 to 35 months old produced similar amounts of antibodies to protect them against flu regardless of whether they received two doses of flu vaccine injection, two doses of live, attenuated nasal spray or one dose of each. Researchers added that one flu vaccine followed by one nasal spray may be the most effective regimen for children below age 2. We routinely administer flu vaccines here in Baton Rouge from September through February.