Aiming to achieve herd immunity naturally is ‘dangerous’, WHO warns-THE HIDNU-17-05-2020
Ryan said the concept of herd immunity is generally used for calculating how many people will need to be vaccinated in a population in order to protect those who are not vaccinated. “We need to be careful while using terms in this way around natural infections in humans because it can lead to a very brutal arithmetic which does not put people, life and suffering at the centre of that equation,” he said.
Health expert warns against herd immunity strategy:
It was mistakenly assumed that as this disease spreads across the world, only the severe cases become apparent while most people would indeed be infected as reflected in sero epidemiology results. This is because the number of people infected in the total population is probably much lower than we expected. This is a serious disease, this is public enemy number one. Ryan added.
Kirkcaldy, from the Centers for Disease Control and Prevention, U.S Though a small study involving just nine patients found a direct correlation between clinical severity and levels of antibody response, “antibody detection and higher titers have not always been found to correlate with clinical improvement in COVID-19”, they say. Also, mild infections can resolve even before detectable antibodies are produced.
Durability of response:
A small study posted in a preprint server bioRxiv found that four rhesus macaques that were infected with coronavirus and recovered did not get reinfected when exposed to the virus 28 days after the first infection. Whether humans too will exhibit such protection is not known, though no cases have so far been reported of people getting reinfected. The detection of over 220 cases of “reinfection” in South Korea was found to be a case of virus remnants being detected and not reinfection or reactivation.
“It remains to be determined whether a robust IgG response corresponds with immunity. According to them, only well-designed longitudinal studies involving those who have recovered from COVID-19 for recurrent illness can help provide the much-needed information about reinfection and the duration of protection by the antibodies.