A recent study has shed doubts about the whole concept of herd immunity, which means that in the absence of any effective vaccine, it may difficult to contain the spread of the COVID-19. The large-scale study which was conducted by Carlos III Health Institute in Madrid was published in the journal Lancet. To conduct the research 61,075 participants all across the country were tested for antibodies after they finished a questionnaire on Coronavirus symptoms. The study revealed that only 5 per cent of the participants in Spain had developed protective antibodies against the virus.