Herd immunity: The seductive myth of Sweden and her response to COVID-19

Wits University's professor Shabir Mahdi explains why the Scandinavian country didn't have a lockdown.

While the world's economies shut down in an effort to curb the spread of the novel coronavirus, Sweden has allowed most businesses to stay open.

The strategy apparently relies on “herd immunity,” in which a critical mass of infection occurs in lower-risk populations that ultimately thwarts transmission.

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Eusebius McKaiser chats to Wits University clinical infectious disease epidemiologist and vaccinologist professor Shabir Mahdi on why this Scandinavian country has chosen to keep its economy open during a pandemic and what herd immunity means.

What herd immunity means is a sort of indirect form of protection against infectious diseases culminating from when a fear percentage of the population has been infected and developed immunity against it.

Professor Shabir Mahdi, Clinical infectious disease epidemiologist and vaccinologist - Wits University

What effectively happens is that because immunity is prevalent in the community, the ability of the virus to transmit between people becomes less successful, he says.

Therefore the ability of a person that is susceptible to being infected with the virus is also reduced. When I say susceptible I am talking about those individuals that don't have any sort of immunity.

Professor Shabir Mahdi, Clinical infectious disease epidemiologist and vaccinologist - Wits University

He says herd immunity evolves in two ways, it could either be because of natural exposure to the virus or bacteria.

Alternatively what can happen is that herd immunity can be accelerated through vaccination.

What we have heard about herd immunity is more in a context to protect those individuals who might actually not respond very well to vaccination but by virtue of the rest of the population develop immunity.

Professor Shabir Mahdi, Clinical infectious disease epidemiologist and vaccinologist - Wits University

Listen below to the full conversation:

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