What is herd immunity and could it work with COVID-19?

What is herd immunity and could it work with COVID-19?

Herd immunity is when a virus can longer spre easily because eugh people are immune to it. That lowers chances of virus jumping from person to person and reaching those who haven’t been infected yet.

People can become immune to certain viruses after surviving infection or being vaccinated. Typically, at least 70% of a population must be immune to achieve herd immunity. But how long immunity lasts varies depending on virus, and it's t yet kwn how long COVID-19 survivors might have that protection.

How easily virus spres also plays a key role.

Say, for example, someone who's infected with a particular virus typically transmits it to two ors. chances of that person passing it on to ors would be lower if half population is alrey immune, said Dr. Walter Orenstein, a vaccine expert at Emory University.

odds of transmission fall furr if even more of population is immune. That could cause new infections to die out.

But if a virus is more infectious, a higher percent of people would need to have immunity to stop spre and achieve herd immunity, Orenstein said.