Interesting, it's similar to what is going on here:

Why the world’s most vaccinated country is seeing an unprecedented spike in coronavirus cases | The Seattle Times

So far, the number of deaths in the Seychelles attributed to the virus is relatively low — 28 out of more than 6,000 cases. But the surge in new cases may also confirm that the vaccines being used in the country have comparatively low effectiveness.

Roughly 60% of the doses administered in Seychelles are vaccines made by the Chinese company Sinopharm that were donated to the Seychelles by the United Arab Emirates. The remaining doses are of the vaccine developed by AstraZeneca and produced by the Serum Institute of India.

In many ways, Seychelles government negotiations for vaccine supplies were savvy and speedy. But the country has ended up using two vaccines that appear to be less effective against symptomatic COVID-19.
The World Health Organization had recently estimated the efficiency of the Sinopharm vaccine at just over 78% for adults under 60, with little data on its success with older patients.

The UAE has asked some who received the Sinopharm vaccine to return for third doses, citing low immune responses, though officials said only a “very small number” need to do so.

Sinopharm is an inactivated virus vaccine like Sinovac.