South Africa has doubled the interval between Pfizer vaccine doses from 21 days to 42 days. What have other countries done and is there evidence to back the change?
In South Africa, people who received their first shot of the Pfizer Covid-19 vaccine must wait six weeks before returning for the second jab.
This follows updated guidance issued by the national Health Department a month ago, in light of new data showing a longer delay between doses could offer more protection.
By last week, Pfizer was the most numerous brand of vaccine being rolled out in South Africa -- with just over 1.5 million people having received their first shot. On Thursday, 300,000 Johnson & Johnson jabs arrived and this week Aspen Pharmacare will release an additional one million doses.
This follows delays in getting Johnson & Johnson vaccines into the country, with some consignments declared unusable because of low production standards. This has led to growing pressure for South Africa to get greater value from the remaining vaccines in its arsenal.
What is the evidence behind the three-week extension between doses, what does this mean for your follow-up appointment and how could it help...