How can we manage the virus AFTER we flatten the curve
By now, most people know what it means to “flatten the curve” through social isolation, masks and hand washing. The next logical question is what will it take for us to get out of lockdowns across the country? The answer will be driven by a mixture of science and policy. In the next few blogs, I will discuss a number of factors on the science that will drive this answer. We will frame this as a set of the right questions since the answers will likely evolve as we get more data.
How infectious are asymptomatic people?
What has been worrying epidemiologists is that asymptomatic people are driving the virus. A recent article in Science describes what might have occurred in China. An epidemiologic model shows that a large percentage (86%) of COVID-19 infections in China were in undocumented patients, people who had little symptoms to no symptoms. Even though those people had only 55% of the transmission rate of documented patients, a large proportion (79%) of the spread was mediated through undocumented patients because of their grater numb The reason for this may be that COVID attaches to ACE2 receptors in the throat and as a result, the virus is present in throat secretions, not just the lung.
There are several implications if this is true:
- Healthcare workers will need to have universal precautions, every health care worker with a mask (something we already do at Rezilir)
- We need to have dramatic and repeated testing to “box in the virus”, not just test those with significant symptoms.
- Even more contact workers are needed to follow-up with patients of who have tested positive.
It is assumed that the virus will infect a very high amount of the population. Some models show up to 50-75%, based on what has happened in prior flu epidemics, which creates what is called “herd immunity” that prevents the virus from spreading further.
5 recent studies show similar numbers all below 20%:
- Germany – a study that sampled 1000 residents in the town of Gangelt showed that 14 percent of the population had antibodies to COVID, 2 percent showing active infection and a total of 15 percent of people who had been infected with the virus.
- Diamond Princess – This was the ship that was quarantined on February 3rd when a passenger boarded the ship on January 20th and stayed on the ship for 5 days and spread the virus. All of the 3711 passengers were tested, ultimately 17 percent of them turned out to be infected
- China – A study of 391 people and 1286 of their close contacts in Shenzen, China who shared a household with someone who had been infected showed that 15 percent of the close contacts were infected.
- NYC – Universal screening of 215 women admitted for delivery at Columbia Presbyterian showed a 15.4% infection rate. Of the 15.4% who were infected 13.9% had no symptoms and 1.9% had symptoms.
- Iceland – A study in the New England Journal of Medicine on 4/14/20 screened 6 percent of the entire population and 13.3% had positive results for infections with COVID-19. Interestingly the percentage of infected participants that was determined through population screening remained stable.
These studies are among the first to understand what percentage of the population is infected. It’s hard to know how to interpret them yet – it could mean that fewer people will ultimately get infected. Or that in all of these situations, the virus could have spread further without isolation strategies. If it is the former scenario, the implication would be profound. So we will keep a close eye out for further studies including those of US hospital workers to see if there are situations where the percentage of the exposed population gets above 20%.
Other questions that we need to answer in upcoming blogs are the following:
- Can prophylaxis be effective?
- How accurate are antibody tests?
- Will antibodies provide immunity?
- Can early treatment be effective?
Meanwhile, the team at Rezilir Health wish you and your loved ones health, strength and HOPE during this difficult time.
Dr. Craig Tanio
1. Li R, Pei S. Substantial undocumented infection facilitates the rapid dissemination of novel coronavirus (SARS-COV2) Science 16 Mar 2020, DOI: 10.1126/science.aab3221
2. Gudbartsson D. Helgason A. et al. Spread of SARS COV2 in the Icelandic Population. NEJM April 14 2020 DOI: 10:1056/NEJMoa2006100