The AstraZeneca adenoviral Covid-19 vaccine: What potential role does it have?

The results of the AstraZeneca adenoviral ChAdOx1 nCoV-190 vaccine trial published in the Lancet today are encouraging, even if the overall efficacy of 70% is lower than the 90-95% being reported for mRNA vaccines from Pfizer-BioNTech and Moderna; and from the Russian Sputnik adenoviral vector vaccine.

The AstraZeneca vaccine is cheaper than the mRNA vaccines and can be stored in a conventional vaccine fridge. Hence, it is an easier vaccine to use in primary care and community settings, including in low and middle income countries. The most commonly reported adverse reactions were fatigue, headache, feverishness, and myalgia. More serious adverse events were rare; none of which were thought to be due to either of the vaccines used in the study.

Based on these results, once the vaccine is approved by the MHRA, I would like to see it rapidly adopted by the NHS. The vaccine is highly suited for use in UK primary care as it can be stored in general practices and given to patients either opportunistically or in dedicated vaccination clinics. It can also be more easily used in care homes and for housebound patients than the mRNA vaccines.

There is ongoing research looking at vaccine combinations and if this research shows positive results, people may benefit from a second vaccine, such as an mRNA vaccine, after receiving an adenoviral vaccine. One caveat for all the Covid-19 vaccines is that we don’t yet know how long the immunity they generate will last. We also don’t yet know if they stop people being infectious.