As the cases of corona increase worldwide, WHO gets concerned. The World Health Organization chief recommended on Monday against just letting the new coronavirus to increase in the expectation of obtaining so-called herd immunity, saying it was "unethical". Tedros Adhanom Ghebreyesus warned against proposals in some countries to let Covid-19 run its course until enough people manifest the immunity needed to naturally curb its transmission. During a virtual press briefing, he stated, "Herd immunity is a concept used for vaccination, in which a population can be protected from a certain virus if a threshold of vaccination is reached." Economy need revival post-pandemic: IAEA Director General Rafael Grossi For measles, for instance, it is considered that if 95 percent of the population is vaccinated, the remaining five percent will also be protected from the spread of the virus. Tedros said, "Herd immunity is achieved by protecting people from a virus, not by exposing them to it." "Never in the history of public health has herd immunity been used as a strategy for responding to an outbreak, let alone a pandemic," he insisted. Leading vaccine maker Johnson & Johnson halts its vaccine production The new coronavirus has killed well over one million people and infected more than 37.5 million since it first surfaced in China late last year. Relying on naturally obtaining herd immunity in such a situation would be "scientifically and ethically problematic", Tedros said. "Allowing a dangerous virus that we don’t fully understand to run free is simply unethical. It's not an option." Tedros pointed to some cases where people are believed to have been infected with the virus a second time. UK: PM Boris Johnson focuses on lockdown to take place in the country