PhD Scientific Days 2022

Clinical Medicine III.

Nasal vaccination, the preferable child-friendly approach for influenza prevention, a systematic review and meta-analysis of RCT-s

Text of the abstract

Introduction
Vaccination coverage against influenza in children needs to be improved.
Since this vaccination is not mandatory, parents' and children's choices are influenced by the fact that influenza prevention is based on predictions, it has to be repeated annually, and children's vaccination schedules are already long. It is costly and the conventional intervention is even painful. If nasal vaccines would prove to be as safe and effective as the injectable forms, we could increase vaccination rates.

Aims
To compare the efficacy and safety of nasal and intramuscular influenza vaccination in children regardless of health conditions.

Methods
Systematic review and meta-analysis based on randomized, active-controlled trials in children and young adults (0-21 years), regardless of health conditions.
A systematic search with our search key was performed in 3 databases (Medline, Embase, Central) after PROSPERO registration.
Our primary outcome, the rate of laboratory-confirmed influenza illness, regardless of strains, and secondary outcomes the adverse events, were visualized in forest plots based on OR+95% confidence intervals. We performed I2 tests to assess statistical heterogeneity.

Results
Based on 13 trials, the pooled OR for getting influenza regardless of strains is 0.63 (95%-CI=0.5-0.8), I2=78. Thus, with the administration of nasal vaccination, it was significantly lower in the nasal group, than in the injectable group.
With the subgroup analysis of multi-center trials the pooled OR is 0.47 (95%-CI=0.35-0.63) with low heterogeneity (I2=35%).
All-cause mortality was low and independent of the interventions. There was no significant difference between the two methods. This is also present for serious adverse events.
Out of the 20 adverse events and reactions analyzed, only nasal discharge (10 articles) OR=1.57 (95%-CI=1.35-1.82), I2=25% and sore throat (7 articles) OR=1.13 (95%-CI=1.01-1.26), I2=0% showed a significant difference with more events occuring in the nasal vaccination group.

Conclusion
Nasal vaccination should be the preferred, child-friendly vaccination type for influenza prevention, as it is as effective and safe. This pain-free, time-saving form may also provide an opportunity for national mass immunization programs in schools and kindergartens.

No funding.