WHO warns that few have developed antibodies to Covid-19

WHO warns that few have developed antibodies to Covid-19

Low Antibody Levels Pose Challenges for COVID-19 Exit Strategies

According to the World Health Organization (WHO), only a tiny proportion of the global population—potentially as few as 2% or 3%—appear to have antibodies indicating they have been infected with COVID-19. This finding has significant implications for the hopes of using herd immunity to ease the transition out of lockdowns and return to pre-pandemic normalcy.In a media briefing in Geneva on Monday, WHO Director-General Dr. Tedros Adhanom Ghebreyesus emphasized the challenges this low antibody prevalence presents. “Easing restrictions is not the end of the epidemic in any country,” Dr. Tedros stated. “So-called lockdowns can help to take the heat out of a country’s epidemic.” His comments underscore the fact that while lockdowns are crucial in controlling the immediate spread of the virus, they are not a cure-all.

The low levels of antibodies in the population suggest that the concept of herd immunity—where a large portion of the community becomes immune to a disease, thereby providing indirect protection to those who are not immune—may not be achievable in the near term. The current serological testing data indicates that the proportion of people who have been infected and developed antibodies is relatively small. Dr. Tedros noted, “Early data suggests that a relatively small percentage of the expanded sample may have been infected,” pointing out that the figure is “not more than 2% to 3%.”These findings have profound implications for public health strategies worldwide. The limited prevalence of antibodies means that achieving herd immunity through natural infection alone is far from realistic in the foreseeable future. It also highlights the critical importance of continuing to follow public health guidelines, including social distancing, mask-wearing, and hygiene practices, as the virus continues to circulate.

The low antibody levels could also affect vaccine distribution and effectiveness. With only a small percentage of the population having developed natural immunity, vaccines will play a crucial role in building broader immunity. However, the slow rate of natural immunity underscores the importance of ensuring widespread and equitable access to vaccines to accelerate the path towards herd immunity.Moreover, the low percentage of people with antibodies suggests that the virus has not yet spread widely enough in many regions to provide significant community protection. This challenges the notion that easing lockdown measures will necessarily lead to a swift resolution of the epidemic. Countries and regions will need to carefully balance reopening strategies with ongoing efforts to control the virus and prevent resurgence.

In summary, the WHO’s findings that only a small fraction of the global population has antibodies to COVID-19 paint a sobering picture of the current state of the pandemic. The low levels of immunity indicate that achieving herd immunity through natural infection is unlikely in the near term and that lockdowns remain a vital tool in managing the epidemic. As we move forward, it is essential to continue robust public health measures and support widespread vaccination efforts to control the spread of the virus and eventually overcome the pandemic.Dr Maria Van Kerkhove, an American infectious diseases expert who is the WHO’s technical lead on Covid-19, said they had thought the number of people infected would be higher, but she stressed it was still too early to be sure. “Initially, we see a lower proportion of people with antibodies than we were expecting,” she said. “A lower number of people are infected.”

Santa Clara county had 1,094 confirmed cases of Covid-19 at the time the study was carried out, but antibody tests suggest that between 48,000 and 81,000 people had been infected by early April, most of whom did not develop symptoms.But even those high figures mean that within the whole population of the county, only 3% have been infected and have antibodies to the virus. A study in the Netherlands of 7,000 blood donors also found that just 3% had antibodies.Van Kerkhove said they needed to look carefully at the way the studies were being carried out. “A number of studies we are aware of in pre-print have suggested that small proportions of the population [have antibodies],” she said. These were “in single digits, up to 14% in Germany and France”. “It is really important to understand how the studies were done.”

That would include asking how they found the people to test. Was it at random or were they blood donors, who tend to be healthy adults? They would also need to look at how well the blood tests were performed. “We are working with a number of countries carrying out these serology studies,” she added. The WHO-supported studies would use robust methods and the tests would be validated for accuracy. The hope will be that people who have had Covid-19 will be able to resume their lives. But Van Kerkhove last week said that even if tests showed a person had antibodies, it did not prove that they were immune.