The Delta variant of the coronavirus can evade antibodies that target certain parts of the virus, according to a new study published on Thursday in Nature. The findings provide an explanation for diminished effectiveness of the vaccines against Delta, compared with other variants.
The variant, first identified in India, is believed to be about 60 percent more contagious than Alpha, the version of the virus that thrashed Britain and much of Europe earlier this year, and perhaps twice as contagious as the original coronavirus. The Delta variant is now driving outbreaks among unvaccinated populations in countries like Malaysia, Portugal, Indonesia and Australia.
Delta is also now the dominant variant in the United States. Infections in the country had plateaued at their lowest levels since early in the pandemic, though the numbers may be rising. Still, hospitalizations and deaths related to the virus have continued a steep plunge. That’s partly because of relatively high vaccination rates: 48 percent of Americans are fully vaccinated, and 55 percent have received at least one dose.
But the new study found that Delta was barely sensitive to one dose of vaccine, confirming previous research that suggested that the variant can partly evade the immune system — although to a lesser degree than Beta, the variant first identified in South Africa.