Health Editor’s Note: We have heard the term ‘herd immunity’ used before this current coronavirus pandemic. Now the concept crops up again in theories as to how COVID-19 can be contained. Herd immunity is simply when a population becomes immune to an infectious disease and then provides indirect protection (herd immunity or herd protection) to those who are not immune to the disease.
Herd immunity has been accomplished for diseases such as measles, mumps, rubella, and chicken pox because there are vaccines for most of the population to take. With coronavirus, there is no vaccine, thus no way to develop an immunity other than to contract the virus and we are seeing that any immunity the body may have to COVID-19, after being sick with the virus, does not seem to last. So, we are not getting protection for the unaffected, because the previously infected can be reinfected…..Carol
My patient caught Covid-19 twice. So long to herd immunity hopes?
by D.Clay Ackerly/Vox
“Wait. I can catch Covid twice?” my 50-year-old patient asked in disbelief. It was the beginning of July, and he had just tested positive for SARS-CoV-2, the virus that causes Covid-19, for a second time — three months after a previous infection.
While there’s still much we don’t understand about immunity to this new illness, a small but growing number of cases like his suggest the answer is yes.
Covid-19 may also be much worse the second time around. During his first infection, my patient experienced a mild cough and sore throat. His second infection, in contrast, was marked by a high fever, shortness of breath, and hypoxia, resulting in multiple trips to the hospital.
Recent reports and conversations with physician colleagues suggest my patient is not alone. Two patients in New Jersey, for instance, appear to have contracted Covid-19 a second time almost two months after fully recovering from their first infection. Daniel Griffin, a physician and researcher at Columbia University in New York, recently described a case of presumed reinfection on the This Week in Virology podcast.