I talked to Dr. Neil Kay of Mayo Clinic, Rochester, MN on how he decides about the safety of his CLL patients leaving “sheltering in place” and re-entering the world. While this interview was conducted before the December 2020 surge, the concepts and decision-making process that guide him in advising his patients remain the same.
He explains the important concept of R0 or reproduction number. This number helps him guide his patients.
R0, pronounced “R naught,” indicates how contagious an infectious disease is. It tells you the average number of people who will contract an infectious disease from one person who has it. For example, if a disease has an R0 of 5 (and that might be about the R0 for COVID-19), a person who has the disease will transmit it, on average, to 5 other people.
There are three possibilities for the potential transmission or decline of a disease, depending on its R0 value:
- If R0 is less than 1, each existing infection causes less than one new infection. In this scenario, the disease will eventually die out.
- If R0 equals 1, each existing infection causes one new infection. The disease will stay alive and stable, but there won’t be a pandemic.
- If R0 is greater than 1, as is the case with COVID-19, each infected person infects more than 1 new person. The number infected with the disease grows, and there could be an outbreak or if wider spread, an epidemic or if global, a pandemic.
Besides R0, Dr. Kay also considers the prevalence of the disease in the patient’s community and his patient’s co-morbidity or other illnesses.
The news with COVID-19 changes fast. Unlike when we did the interview, we do now have an effective vaccine, at least for the general population.
But Dr. Kay, like me and Dr. Fauci, sees COVID-19 as a long-term issue for CLL patients and paints a realistic picture of the world we live in; a world where not everyone gets vaccinated or responds to the vaccine or wears a mask.
I can’t say please enjoy my interview with Dr. Kay, but I can say, it is important that you give a listen. He does talk about a way through vaccine and herd immunity.
We are all in this together.
Brian Koffman MDCM (retired) MS Ed
Co-Founder, Executive VP and Chief Medical Officer
CLL Society, Inc.