SAN FRANCISCO IS LEADING THE WAY TO HERD IMMUNITY

SAN FRANCISCO IS LEADING THE WAY TO HERD IMMUNITY

Subject : Science & tech

Context : Top epidemiologists have predicted that San Francisco, California will be the first major American city to arrive at the possible endgame of the pandemic — herd immunity.

Concept :

• Experts believe San Francisco’s vaccination drive is largely to thank for its success in combating the virus.
• So far, nearly 80 per cent of all adults have already received at least one dose of the vaccine in the city, according to San Francisco health department data.

Herd Immunity

• Herd immunity is when a large number of people are vaccinated against a disease, lowering the chances of others being infected by it.
• When a sufficient percentage of a population is vaccinated, it slows the spread of disease.
• It is also referred to as community immunity or herd protection.
• The decline of disease incidence is greater than the proportion of individuals immunized because vaccination reduces the spread of an infectious agent by reducing the amount and/or duration of pathogen shedding by vaccines, retarding transmission.
• The approach requires those exposed to the virus to build natural immunity and stop the human-to-human transmission. This will subsequently halt its spread.