Is the coronavirus playing games with the world? Do lockdowns have a lasting effect? Hong Kong was a rare success story in the global war on coronavirus. But it also showed what happens when such measures as social distancing, hygiene and protective gear are relaxed too soon. In the past week, confirmed cases in Hong Kong suddenly doubled, mainly due to overseas imports, prompting Hong Kong Chief Executive Carrie Lam on Wednesday, March 25 to bar all non-residents from the territory.
This pattern of ebb and surge, which is unfolding also in China, Singapore and Taiwan, begs questions. Is the lockdown model for containing coronavirus at fault? After all, people do get fed up staying at home. Or was the lifting of restrictions premature? These questions lead to another: Maybe the virus did not in the first wave reach what epidemiologists call “critical mass” i.e., infecting enough people for the “herd effect” to kick in. It therefore returned for a second visit.
The “herd effect” or “herd immunity” – another term used by those scientists – happens when a large proportion of a population develops an immune response to a certain disease, forcing the virus to run out of hosts and retreat. Large-scale vaccinations may trigger this effect by disrupting the chain of infection.
But the size of this proportion – and therefore critical mass – varies from virus to virus and has not been discovered yet in the case of covid-19. READ MORE