Coronavirus: no certainty on herd immunity until we know more about vaccines and variants
- Early estimates for reaching herd immunity were based on the original strain but estimates for emerging variants are higher
- As countries roll out different vaccines at different speeds along with control measures, there may be patchwork of risks in future
This is the sixth in a series about China’s plans to reopen its borders amid the Covid-19 pandemic. Here, Simone McCarthy and Zhuang Pinghui look into the problems in pinning down when “herd immunity” can be achieved.
Now, as a handful of nations have vaccinated at least half of their population, attention has turned to questions of when herd immunity can be achieved and what it will look like.
Crossing that unknown threshold could mean leaders of “zero-tolerance” countries open their borders, and offices and schools fully reopen in others.
“Many policymakers link herd immunity to the successful control or end of the pandemic, but it depends on how you define the end of the pandemic,” said Kwok Kin-on, an assistant professor at the Chinese University of Hong Kong’s JC School of Public Health and Primary Care.