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A shortage of Bharat Biotech's Covaxin in some areas has meant that some people have been unable to have their second dose within the recommended time frame.
A shortage of Bharat Biotech's Covaxin in some areas has meant that some people have been unable to have their second dose within the recommended time frame.
We don’t have data on the effectiveness of a single dose of Covaxin, or an extended delay between 2 doses of Covaxin although for other vaccines an extended gap between first and second doses has produced a greater immune response (https://www.ox.ac.uk/news/2021-06-28-delayed-second-dose-and-third-doses-oxford-astrazeneca-vaccine-lead-heightened).
It is likely that a second dose of a different vaccine would be safe and boost the immune response although data are not available for Covaxin mixed and matched with other vaccines.
To be clear, having only a single dose of Covaxin will not in itself cause any harm – the harm could come if a person is infected with COVID-19 after a single dose as they will not be as well protected against severe outcomes.