Abstract
Live attenuated measles-containing vaccine (MeV) delivered by aerosol inhalation (Aer) was trialled in millions of Mexican school children in the 1980s and a clinical trial involving approximately 5,000 South African school children reported similar safety and higher long-term immunogenicity for Aer vs injected MeV—both used a ‘home-made’ nebuliser. Immunogenicity of measles-mumps-rubella vaccine (MMR) via Aer has not been studied in young adults with waning vaccine-acquired immunity using a modern vibrating mesh nebuliser (VMN). At Otago in 2023, 28% of 725 health science students were Measles (Me) and/or mumps (Mu) antibody (Ab) negative and required a booster MMR. We randomised students requiring MMR to Aer or intramuscular (IM) MMR and gave Me and Mu Ab positive students Aer MMR to assess immunogenicity and safety. NZ Immunisation Handbook contraindications to MMR were used as exclusions for both IM and Aer.
Consenting students (229) received MMR by Aer (166) via the Aerogen VMN or IM (63). Self-reported symptoms were captured at 12 h, 24 h and 48 h by text message-prompted REDCap survey, and in-person at days 4, 7 and 14. Systemic symptoms were recorded by presence and graded by severity; respiratory symptoms as present or absent.
Common systemic symptoms were: headache (17% IM; 22% Aer), fatigue (29% IM; 30% Aer) and muscle/joint pain (8% IM; 6% Aer); of these, severity was low grade in 91% IM vs 94% Aer. Any respiratory-related symptoms until 48 h were reported by 14% IM vs 35% Aer (p < 0.01) and from 48 h until 14 d in 10% IM vs 19% Aer (p = 0.093).
Overall, non-respiratory systemic symptoms post-MMR were similar for Aer and IM. Occurrence of any respiratory symptom was more common for Aer, 2.5-fold during the initial 48 h and 1.9-fold from 48 h to 14 d.