The majority of the world now has antibodies against COVID-19, indicating that infection rates may be way higher than previously reported, according to a new study. New research has indicated that around two-thirds of the global population may have antibodies to SARS-CoV-2, either from vaccination or being infected with the virus.
Scientists from the World Health Organization (WHO) reached these findings by looking at hundreds of different seroprevalence studies from January 2020 to April 2022, encompassing information on over 5 million people from around the world. Importantly, over 40 percent of these studies focused on people from low- to middle-income countries who are often overlooked in this kind of research.
Based on this sample, they estimated that the global seroprevalence of SARS-CoV-2 – the proportion of people who had antibodies to the virus – had risen from 7.7 percent in June 2020 to 59.2 percent in September 2021. Since people have continued to become infected and receive vaccines since then, that figure has likely risen further.
“This study on global seroprevalence of SARS-CoV-2 antibodies found that while seroprevalence has increased over time, a third of the global population tested negative for antibodies against the virus as of September 2021 estimates,” the study authors said in a statement.
The authors conceded that some countries may have been underrepresented in the sample, while others were likely overrepresented, but either way, it appears the number of estimated global COVID-19 cases has been underestimated.
As of November 9 2022, there have been 630 million confirmed cases of COVID-19, including 6.5 million reported deaths, according to the WHO’s dashboard. If this latest study is on point, it would suggest that perhaps billions of people have come into contact with the virus.
Unfortunately, however, it doesn’t necessarily mean all of these people are immune to the disease just because they have antibodies.
“While antibodies persist in most infected individuals for up to year (with early evidence pointing at up to 18 months), the reinfection risk with the immune-escaping Omicron variant is reported to be much higher than in previous [variants of concern] in both vaccinated and previously infected individuals, indicating that the presence of antibodies is less indicative of a level of protection against infection,” the study reads.
Scientists around the world are still grappling to understand antibodies and protection against COVID-19, and there are many finer points about seroprevalence that are yet to be known. Nevertheless, the researchers behind the new study believe their work underlines the need to keep tabs on how the world is slowly becoming accustomed to this terrible virus.
“As we enter the third year of the COVID-19 pandemic, implementation of a global system or network for targeted, multi-pathogen, high-quality and standardized collaborative serosurveillance is a crucial next step to monitor the COVID-19 pandemic and contribute to preparedness for other emerging respiratory pathogens,” it adds.
The new study is published in the open-access journal PLOS Medicine.