Seychelles, which has vaccinated the largest proportion of its population of any country against the coronavirus, said active cases of the disease more than doubled in the week to May 7.
The health ministry of the archipelago off Africa's east coast said in a statement on Monday that 2,486 people currently have COVID-19 and 37% of those have received two vaccine doses. The number of active cases rose from 1,068 a week earlier.
Sinopharm shots were issued to 57% of those who were fully inoculated and the rest with Covishield, a vaccine made in India under license from AstraZeneca Plc.
The Seychelles, a group of palm-fringed tropical islands, last week imposed curbs including closing schools, canceling sports events and banning mingling of households, measures last seen in December.
The country had raced to vaccinate its population of just under 100,000 - first with a donation of Sinopharm doses and then with a gift of Covishield shots, so it could reopen to the tourists that are the lifeblood of its economy.
Daniel Lucey, clinical professor of medicine at Dartmouth Geisel School of Medicine, said in a blog last week that data on genetic sequencing are not yet available for infections in Seychelles in April.
Still, the B.1.351 variant, first identified in South Africa late last year, was found in the Seychelles in February, he said. AstraZeneca's vaccine appeared to be less effective against that variant in a study, and South Africa halted plans to use it.
A comparison between Sinopharm, Covishield and unvaccinated infected persons could be done using genetic sequencing and data on the severity of their infections, Lucey said.