The highly transmissible Delta variant of coronavirus has rendered the prospect of herd immunity, where the majority of a country's population becomes immune to a virus, difficult, the head of the UK's Oxford Vaccine Group has warned.
The former group of conditions are called immunodeficiencies. These can exist from birth as a result of genetic alterations, though they are very rare. They can also be acquired later in life through many different causes. These include malnutrition, obesity, diabetes and HIV infection. Immunocompromised: How Will COVID-19 Vaccines Work on Compromised Immune Systems? Here s What We Know.