The World Health Organization said that more than two-thirds of the world’s population probably have significant levels of Covid-19 antibodies, meaning they have either been infected or were vaccinated. In a summary of studies from around the globe, the organization said that the so-called seroprevalence rates surged to 67 per cent in October from 16 per cent in February of 2021.
People who have both been infected with Covid and vaccinated have the best protection against severe outcomes, according to most studies, though it’s unclear if that will be true with new variants, the WHO said. Data show lower levels of seroprevalence in children aged 9 and under and in people over 60 compared with those in their 20s, the WHO said. In low- and middle-income countries, most seroprevalence indicates past infections rather than vaccinations.
The presence of antibodies generally wanes over time and the level and persistence of immunity depend on a host of factors, the health body said, adding that further studies are necessary to determine how quickly protection diminishes.
