Coronavirus

The UK and California (CA) are two very different places with different demographics but they are now closely tied as having two of the hottest COVID-19 outbreaks in the world.   The UK infection rate is currently at 0.73% of its total population over the last 2 weeks, second only to the USA at 0.86%, with CA leading at 1.48%.   Both the UK and CA have instituted masking and stay-at-home orders with varying degrees of compliance and success so it is actually somewhat surprising that these two regions got so hard hit.   Masking compliance is 60% and 80% respectively in the UK and CA, and social distancing compliance is -30% and -40% respectively in the UK and CA.   This bodes ill for other states and countries that have looser mitigation measures. The UK’s high infection rate is apparently 80% due to the new variant (B.1.1.7) in the UK that contains the N501Y mutation (also seen in a South Africa variant).   While this new variant does not cause more severe illness, it does spread more

The solution to the COVID-19 pandemic is at hand and it could substantially reduce deaths in Florida and the USA.   Both the Pfizer/BioNTech and Moderna vaccines have proven to be highly effective with generally mild side-effects.   One question is how to get them distributed most efficiently to minimize the future death count.   So far healthcare workers and nursing home residents have been the phase 1 recipients.   The CDC has recommended that frontline essential workers such as first responders, teachers, and grocery workers, and those 75 and over should be next in line.   In Florida Governor DeSantis has opted to make those 70 and older go to the front of this second group with the reasoning that they are much more vulnerable than 20-yrs old frontline workers.   I agree. The overall risk of a population group should determine its order in the line for vaccines.   This means the risk of infection multiplied by the risk of dying after being infected.   Frontline workers could be

Most COVID-19 infections evolve from exposure to positive tests to hospitalizations to deaths. This well-defined pattern allows us to forecast the pipeline of confirmed cases to hospitalizations to deaths with a fair amount of accuracy. For example Thanksgiving travels and gatherings exposed a large portion of the population to the novel coronavirus causing positive test cases to rise now, 7-10 days afterward.   5-7 days after that the serious cases go to hospitals.   Another week later they result in a favorable discharge or death.   When the community infection rate is high and the positivity measure (percent of tests returning positive) is high, only the serious cases get tested as in the early days of the pandemic this spring.  The average lag time from cases to deaths was only 5 days and the case fatality rate (CFR = deaths/cases) was also high (see figure above).   As testing availability improved and the positivity rate dropped and more asymptomatic and mildly symptomatic cases

Currently, there is a very small number of Americans that have gained immunity from vaccination trials.   The FDA would probably approve the Pfizer vaccine by Dec 10 th and the Moderna one by Dec. 20 th .   By the end of this year, Pfizer and Moderna would have supplied enough vaccines to permit 20M Americans to have had their first shot.   By early next year, 19M Americans would have gained immunity from these two shot vaccines (taking into account the current estimated 95% effectiveness of these vaccines).   Many people estimate that enough vaccine would be available to vaccinate 25M-30M Americans every month in 2021 subject to logistical and psychological constraints (deep blue area in the graph below).   Thus vaccine “herd immunity threshold = 230M” could be reached in the USA by the end of summer.   Herd immunity could actually be reached sooner than that.   Currently over 14M Americans have gained immunity from being infected by SARS-Cov-2.   The immunity may not be perfect but