The AstraZeneca vaccine, developed in partnership with the College of Oxford, was one of many first vaccines obtainable to be used within the UK and world wide through the COVID pandemic.
However most of these had been first and second doses – solely a bit of over 56,000 doses of AstraZeneca had been given as booster doses as of Might 2022. The overwhelming majority of third doses administered within the UK have been Pfizer (30.1 million doses) and Moderna (9.four million).
So regardless of being a superb vaccine, the usage of AstraZeneca within the UK has declined throughout the pandemic. It’s additionally not used a lot elsewhere in Europe, or within the US the place it has but to be accepted.
The rationale for its restricted use in high-income nations may very well be a mixture of two components. First, it’s seemingly that the mRNA vaccines (particularly these manufactured by Pfizer and Moderna) are perceived to be much more efficient than AstraZeneca. And second, the vaccine’s repute took a success when some individuals who obtained this vaccine subsequently developed blood clots.
On the primary level, some analysis has indicated the mRNA vaccines supply barely greater ranges of safety in opposition to beforehand dominant variants, together with delta. A 2022 examine from the Netherlands that measured antibody ranges in opposition to SARS-CoV-2 following vaccination confirmed Pfizer and Moderna carried out higher than the viral vector vaccines (together with AstraZeneca). However one caveat right here is that the contributors who obtained the mRNA vaccines had been a lot youthful than the AstraZeneca recipients. Immune responses sometimes wane quicker in older populations.
The general public fallout from the blood clot scares, related to AstraZeneca however not with Pfizer or Moderna, additionally affected the vaccine’s rollout. The vaccine remains to be licensed to be used in youthful adults within the UK, who had been deemed to be at greater threat of blood clots following the AstraZeneca vaccine. Nonetheless, the UK’s Joint Committee on Vaccination and Immunisation really useful that folks aged 39 and beneath must be provided a substitute for AstraZeneca the place potential.
These adversarial occasions gained important media protection, and public confidence within the AstraZeneca vaccine was actually knocked within the UK and past. For instance, in April 2021, Denmark turned the primary European nation to stop utilizing the vaccine, with Norway following quickly after. Across the similar time, a number of Canadian provinces briefly suspended the AstraZeneca vaccine for folks beneath 55 as a precautionary measure. All of this got here amid excessive ranges of COVID in these nations and elsewhere, and at a time when international demand for COVID vaccines drastically outstripped provide.
These considerably kneejerk reactions made waves additional afield. For instance, analysis my colleagues and I carried out in Ghana highlighted how folks had noticed the responses in Europe and North America. The end result was elevated hesitancy in the direction of the AstraZeneca vaccine.
Regardless of all this, the UK’s Medicines and Healthcare merchandise Regulatory Company, the European Medicines Company and the World Well being Group continued always to advocate the vaccine, based mostly on its security and effectiveness file.
An essential vaccine for the growing world
The proportion of the Ghanaian inhabitants that has obtained a number of doses of any COVID vaccine is simply over 30%. Our 2022 analysis in Ghana signifies that vaccine hesitancy charges amongst these at present unvaccinated ranges between 30%-50%, relying on the inhabitants surveyed.
An April 2022 briefing by the Ghana Well being Service (not revealed on-line) indicated that 43% of the 28 million doses obtained in Ghana have been AstraZeneca. Of the vaccines administered in March 2022, 57% had been AstraZeneca.
Among the many causes for a choice for AstraZeneca, there can be concerns round provide, price and logistical points. For instance, the vaccine requires solely common fridge storage, in contrast with the mRNA vaccines which should be frozen. For these causes the AstraZeneca vaccine is significant for Ghana, together with many different lower-income nations. Excessive native and international confidence is important to make sure a profitable vaccination marketing campaign with excessive uptake.
The UK and lots of different high-income nations are more likely to proceed predominantly utilizing mRNA COVID vaccines. Nonetheless, a lot of the data we have now round “which vaccine is best” pertains to earlier variants fairly than omicron. Because the virus continues to evolve, so should the proof base.
There may be an rising physique of proof that “mixing and matching” vaccine sorts is protected and efficient, and should even generate stronger or broader immune responses over time. On this gentle, there may very well be a job for AstraZeneca or different vaccines akin to Novavax, alongside mRNA vaccines.
In the long run, we want a vaccine that may shield in opposition to a number of variants and even all coronaviruses.
For a lot of high-income nations in 2022, the mRNA vaccines are the vaccine of selection, fairly than AstraZeneca. The mRNA vaccines are additionally being manufactured in sufficiently giant volumes to make provide a lot much less of a difficulty than it was earlier within the pandemic. These are all essential components for nationwide decision-makers. Nonetheless, it’s essential to emphasize that the AstraZeneca vaccine is a protected and efficient product, and stays an important software to underpin the worldwide response to the pandemic.