A new Spanish study suggests herd immunity may never be a viable way to control the COVID-19 pandemic.
The study, which was published in medical journal The Lancet, tested more than 60,000 people and estimated that only 5 percent of the Spanish population has developed antibodies for the coronavirus.
The study also showed that coastal areas in Spain had an even lower prevalence of antibodies at just 3 percent.
It also found that 14 percent of people who had tested positive for the antibodies on the first test, no longer had the antibodies in subsequent tests weeks later. This could mean the antibodies only provide a very short period of immunity
This is despite Spain being one of the worst hit countries in Europe with more than 250,000 confirmed cases and 28,000 deaths.
"Despite the high impact of Covid-19 in Spain, prevalence estimates remain low and are clearly insufficient to provide herd immunity," the study noted.
"This cannot be achieved without accepting the collateral damage of many deaths in the susceptible population and overburdening of health systems.
"In this situation, social distance measures and efforts to identify and isolate new cases and their contacts are imperative for future epidemic control."
Herd immunity is only achieved when enough people - around 70 to 90 percent of the population - become immune to the virus.
The study is one of the largest of its kind on COVID-19 in Europe.
Similar studies in the US and China have also cast doubt on whether herd immunity could actually be achieved with COVID-19.
Sweden has made headlines throughout the pandemic over its desire to get herd immunity.
Instead of enforcing a lockdown or distancing measures, Sweden introduced voluntary guidelines. So far it has had over 73,000 confirmed cases and 5000 deaths.
On Tuesday (local time) Swedish health authorities said the number of cases were dropping thanks to people social distancing.
