Top experts at the World Health Organization warned on Monday that antibodies might not be produced at the rate previously thought, according to new research into how the human body reacts to COVID-19.
Maria van Kerkhove, the WHO's technical lead on COVID-19 and expert infectious disease epidemiologist, said many global studies have found "a very low proportion of... evidence of antibodies."
"The range is between one and ten percent," she said, depending on the study and its technical specifications.
Van Kerkhove said this number is important, as it's the percentage of the population that can defend against a virus that is important when assessing if so-called "herd immunity" is possible.
"What these... studies indicate to us is that there is a large proportion of the population which remains susceptable [to catching COVID-19]."
This theory, often referred to as "herd immunity," originates from vaccinology and argues that if enough of the population has the antibodies (or is vaccinated) to fight the virus, the virus will not be able to spread or take hold. There is currently no accurate picture of what level of humanity would have to have COVID-19 antibodies present - either from catching the virus or from a vaccine - to reach this level, according to van Kerkhove.
She reiterated that quaratining and testing continues to be the best way to fight the spread of the virus.
"We do have tools at our disposal to be able to prevent transmission from happening," van Kerkhove added.
"Herd immunity" criticized
Maria van Kerkhove's colleague, Mike Ryan, had stronger words for those hoping "herd immunity" could be achieved, and therefore the worldwide lockdown conditions could be lifted.
He said the term originated in "veterinary" science, where "an individual animal doesn't matter."
"Humans are not herds," Ryan said. "It can lead to a very brutal arithmetic which does not put life, and people, and suffering at the center of that equation."
Check out The Pandemic Playbook, CGTN Europe's major investigation into the lessons learnt from COVID-19.