As supplies of COVID-19 vaccines have become more plentiful in poor nations, many are tuning down certain shipments.
A document from the World Health Organization’s global vaccine supply effort COVAX shows (PDF) that low-income countries have declined millions of doses of AstraZeneca's Vaxzevria, Reuters reports.
Since the relief initiative began, AstraZeneca has been its most prolific supplier. But that’s changing quickly. Of 200 million COVAX doses assigned to 61 lower-income countries during a six-month period that will end in September, only a small portion will be from AZ.
Countries refused to accept nearly 35 million AZ shots, opting instead for those made by Pfizer-BioNTech, Moderna and Johnson & Johnson, according to the document.
With supplies more accessible, countries are turning away from Vaxzevria largely because of its shorter shelf life, according to the report. Many poor countries lack the infrastructure to distribute vaccines quickly enough to avoid their expiration date.
Vaxzevria has a shelf life of six months. Covishield, the vaccine produced through AZ’s partnership with the Serum Institute, has a nine-month shelf life thanks to a recent WHO extension. AZ is working with regulators to get the same extension for Vaxzevria, the company has said.
While the 61 nations requested a combined 70 million doses from Pfizer and 40 million from Moderna, they asked for only 16.5 million from AZ. There was a similar number of shots requested from Chinese vaccine suppliers Sinopharm and Sinovac, the document said.