LAIV well tolerated among children with cystic fibrosis
Receipt of the nasal live-attenuated influenza vaccine did not increase risk for respiratory deterioration or all-cause hospitalization among children with cystic fibrosis, study data showed.
Constantina Boikos, MScPH, of McGill University in Montreal, and colleagues assessed vaccine tolerance among 168 children, aged 2 to 18 years, with cystic fibrosis who received LAIV between October 2012 and January 2013. Study participants were followed for 56 days after initial vaccination. Days 0 to 28 after LAIV were considered the at-risk period and days 29 to 56 were considered the non-at-risk period.
Approximately 38% used inhaled and/or nasal corticosteroids at baseline, 19% used inhaled antibiotics and 3% used azithromycin.
Incidence rates for respiratory deterioration and all-cause hospitalizations did not differ between the at-risk period and the non-at-risk period. Seven respiratory deteriorations occurred and all required hospitalization. Three of these incidents occurred during the at-risk period and four in the non-at-risk period. Influenza virus was not detected in any respiratory deterioration occurrence.
During the at-risk period, two oral antibiotic treatments were administered for respiratory complaints compared with six during the non-at-risk period.
Eleven all-cause hospitalizations occurred. Of these, six were in the at-risk period and five were in the non-at-risk period.
Sixty-four participants experienced at least one symptom in the first week after vaccination. The most significant risks were for joint pain (RR=10.5; 95% CI, 2.5-44.08), muscle aches (RR=9.67; 95% CI, 3-31.12), and vomiting (RR=7.67; 95% CI, 2.35-25.05).
Onset of fever within 6 days after vaccination occurred in 35% of participants. The highest number of fevers were reported on the fourth day after vaccination (n=42).
During the at-risk period, children younger than 9 years were more likely to experience runny nose and vomiting compared with children aged 9 years and older. Wheezing was most likely to be reported during the at-risk period. The day of vaccination had the highest incidence of wheezing.
Participants using inhaled or non-inhaled corticosteroids had an increased risk for worsening cough during the at-risk period, regardless of inhaled corticosteroid use at baseline. Children who used nasal corticosteroids at baseline were less likely to have runny nose and nasal congestion during the at-risk period compared with participants who were not using the medication. On days 0 to 6 post-vaccination, children taking nasal corticosteroids had a decreased risk for runny nose and nasal congestion compared with children who were taking nasal corticosteroids at baseline.
“Overall, although we identified an increased risk of [adverse events following immunization] after LAIV vaccination, in particular an increase in wheezing, we did not find an increased risk of respiratory deterioration associated with LAIV in our study population. Given the clinically severe impact of influenza infection in a child with [cystic fibrosis], as well as LAIV’s improved efficacy over [trivalent inactivated influenza vaccine], particularly in young children, the risks associated with infection outweigh the risk of minor respiratory and systemic symptoms associated with the vaccine,” the researchers concluded.
Disclosure: Some of the researchers report financial ties with AbbVie, GlaxoSmithKline, Pfizer, Sage, Sanofi Pasteur, Novartis and Takeda.