COVID is surging in the world’s most vaccinated country. Why?
The small archipelago nation of Seychelles, northeast of Madagascar in the Indian Ocean, has emerged as the world’s most vaccinated country for COVID-19.
How can this be happening? There are several possible explanations:
the herd immunity threshold has not been reached — 62% vaccination is likely not adequate with the vaccines being used
herd immunity is unreachable due to inadequate efficacy of the two vaccines being used
variants that escape vaccine protection are dominant in Seychelles
the B1617 Indian variant is spreading, which appears to be more infectious than other variants
mass failures of the cold-chain logistics needed for transport and storage, which rendered the vaccines ineffective.
What does the country’s experience teach us about variants, vaccine efficacy and herd immunity?
Let’s break this down.
Variants can escape vaccine protection
There are reports of the South African B.1.351 variant circulating in Seychelles. This variant shows the greatest ability to escape vaccine protection of all COVID variants so far.
The efficacy of the Sinopharm vaccine against this variant is unknown, but lab studies show some reduction in protection, based on blood tests, but probably some protection.
However, no comprehensive surveillance exists in the country to know what proportion of cases are due to the South African variant.