Writing in Science in July 2022 Dr Eric Topol and Dr Akiko Iwasaki reflected on the “unprecedented success” of the mRNA vaccine programme in response to Covid-19. The next step, they suggested, is to translate the efficiency of the Covid-19 vaccines into nasal vaccine development. Meeting a “major unmet clinical need” shines a light onto the possibility of nasal vaccines.

The “allure for achieving mucosal immunity, complementing, and likely bolstering the circulating immunity achieved via intramuscular shots” appeals to Topol and Iwasaki, who draw our attention to what they describe as “substantial attrition” in the efficacy of current vaccines. With reference to specific variants and subsequent “variant-chasing” the “only path”, they say, will be nasal or oral vaccines.  

What are our options on the nasal vaccine scene? Topol and Iwasaki are ready with examples, 4 of which have progressed to Phase III trials: Bharat Biotech, Codagenix, Beijing Wantal Biological, and Razi Vaccine and Serum Research Institute. Despite these positive developments, they recognise that there are challenges to providing effective and safe nasal vaccines, which have been encountered in the past.

Currently FluMist is the only intranasal vaccine approved by the FDA, but it has a limited approval population. Furthermore, financial reticence leads to “substantial delays in manufacturing at scale, regulatory approval, and distribution.” They call for investment such as that in Operation Warp Speed (OWS) in the US to “get ahead of the virus and build on the initial success”. 

It remains to be seen whether there will be an appetite for this kind of development, particularly given the pace of the virus’ mutation and variation.