The agency said this pragmatic approach could be considered as a response to exceptional epidemiological circumstances.
WHO's recommendation at present is that the interval between doses may be extended up to 42 days (6 weeks), on the basis of currently available clinical trial data, it said, adding: Should additional data become available on longer intervals between doses, revision of this recommendation will be considered.
Hard-hit Britain, for example, has decided to delay for as much as 12 weeks and data from that expansion could help contribute to possible revisions in the WHO recommendation, said WHO spokeswoman Dr. Margaret Harris.
In the recommendations, WHO added that countries seeking to extend the interval should make sure that vaccinated patients can still have access to a second dose.
The agency also said it also does not recommend COVID-19 vaccination of travelers unless they face high risks or qualify as priority cases.
WHO also said symptomatic reinfection by the coronavirus within six months of a first infection is rare, so people who have had the illness within the previous six months may delay vaccination until near the end of this period.
WHO said there was currently no evidence on the need for a booster dose, and said there was no data available on the interchangeability of the Pfizer-BioNTech vaccine with other COVID-19 vaccines. It also cited a lack of evidence about whether vaccination reduces the risk of transmission of the virus to other people.
Business Standard has always strived hard to provide up-to-date information and commentary on developments that are of interest to you and have wider political and economic implications for the country and the world. Your encouragement and constant feedback on how to improve our offering have only made our resolve and commitment to these ideals stronger. Even during these difficult times arising out of Covid-19, we continue to remain committed to keeping you informed and updated with credible news, authoritative views and incisive commentary on topical issues of relevance.
We, however, have a request.
As we battle the economic impact of the pandemic, we need your support even more, so that we can continue to offer you more quality content. Our subscription model has seen an encouraging response from many of you, who have subscribed to our online content. More subscription to our online content can only help us achieve the goals of offering you even better and more relevant content. We believe in free, fair and credible journalism. Your support through more subscriptions can help us practise the journalism to which we are committed.
Support quality journalism and subscribe to Business Standard.