Coronavirus disease (COVID-19): Herd immunity, lockdowns and COVID-19 (WHO)
https://www.who.int/news-room/questions ... d-covid-19
To safely achieve herd immunity against COVID-19, a substantial proportion of a population would need to be vaccinated, lowering the overall amount of virus able to spread in the whole population. One of the aims with working towards herd immunity is to keep vulnerable groups who cannot get vaccinated (e.g. due to health conditions like allergic reactions to the vaccine) safe and protected from the disease.