Chile today begins offering a fourth shot of the coronavirus vaccine to immunocompromised individuals over twelve, becoming the first Latin American country to administer the additional jab.
With 87% of the population double vaccinated and 59% having received the first booster, Chile boasts one of the world’s highest vaccination rates. However, the rapidly spreading Omicron variant has increased cases, compelling the government to approve a second booster of the Pfizer, Sinovac and AstraZeneca vaccines.
Israel is among the few other countries to offer a fourth shot. Meanwhile, the UK and South Korea have ordered doses in anticipation of future boosters.
Critics claim that a fourth booster could be ineffective and unsustainable. The “original antigenic sin” suggests that vaccines are built around the original virus, proving less effective against subsequent variants. Supporting data shows a mere 40% efficacy ten weeks after the shot. Experts suggest that it is unreasonable to boost entire populations every six months when efficacy declines.
Despite criticism, many countries will likely follow Chile’s lead and administer fourth doses in the coming months. Likewise, expect medical companies to develop sustainable alternatives to booster shots such as pan-coronavirus vaccines that target all coronaviruses, while simultaneously developing Omicron-based boosters.
Ava is an Analyst and regular contributor to the Daily Brief. She focuses on political and economic developments across Latin America and the Caribbean.