Very pleased to report that our JAMA paper on public health interventions with the epidemiology of the COVID-19 outbreak in Wuhan based on analysis of 32,000+ lab-confirmed COVID-19 cases in Wuhan till Mar 8 appeared on April 10. See below for a summary.
jamanetwork.com/journals/jama/…
jamanetwork.com/journals/jama/…
This is an updated analysis of that reported in the MedRxiv pre-print posted on March 6 by including 32K cases until March 8 and adding a fifth period after a universal symptom screening that was implemented on February 17-18.
Multi-faceted public health interventions using both social distancing AND centralized isolation and quarantine crushed the curve! These findings may help other countries and regions to combat the global pandemic. 
The key PH interventions, including lockdown, traffic ban, home quarantine, centralized isolation of infected, quarantine of symptomatic subjects and close contacts of infected, and a universal symptom survey, in conjunction with early treatment, substantially slowed the spread.
Without interventions (before 1/23), the effective reproduction number R>3.0. It dropped to 1.0 on Feb 6 using social distancing launched on Jan 23, and further to as low as 0.1 on Mar 8 after centralized isolation & quarantine launched on Feb 1 and universal screening on Feb 17.
Household transmission is most common. Social distancing helps reduce community transmission, but household members and close contacts may still be infected and might infect others in the community under home quarantine.
Centralized isolation and quarantine helps reduce transmission among family members within households. Social distancing helps flatten the curve, and centralized isolation and quarantine helps bend the curve.
The roles of social distancing and centralized isolation and quarantine are complementary for controlling the outbreak: social distancing for blocking the between-household transmissions chain, and centralized isolation and quarantine for blocking within-household transmission.
The field hospitals in Wuhan admitted test-positive patients with MILD/MODERATE symptoms, so these patients can receive early treatment & be closely monitored by medical staff to prevent them from becoming severe. This also helps block transmission chain & protect family members
The following figure from Chen, et al (Lancet, 2020) summarizes the key functions and characteristics of the field hospitals in Wuhan thelancet.com/journals/lance…
The MA field hospitals admit mild/moderate cases according to the Boston Globe article. I am not sure whether other states do.
bostonglobe.com/2020/04/08/met…
bostonglobe.com/2020/04/08/met…
The results that social distancing reduces R to be stuck around 1 have been replicated in several countries, such as Italy. This means one person is still infected by one infected person on average using this measure
Household transmission under home quarantine is particularly a concern for low income families and under-representative minorities because of their poor housing conditions. The top 8 towns in MA with highest positive test rates are all low income towns with high % of URMs
This raises a concern of worsening health disparity. There is a pressing need for developing effective isolation and quarantine measures to segregate infected subjects by preventing them from infecting family members & close contacts in poor neighorhood
jamanetwork.com/journals/jama/…
jamanetwork.com/journals/jama/…
To fully control for the epidemic, multi-faceted measures are needed, which include five pillars: social distancing, wide testing, contact tracing, isolation of infected patients and quarantine symptomatic subjects and close contacts, and treating infected patients.
It took Wuhan 6.5 weeks to reduce R from >3 to 0.1 through these measures from January 23 to March 8: 1.5 week of social distancing and 5 weeks of centralized isolation and quarantine. The city was reopened on April 8 after 2 weeks of 0 confirmed cases.
Each country is different, detailed effective implementation of these measures needs to adapt to each country’s own situation and culture by learning from other countries: public health implementation, health care implementation and society implementation.
Centralized quarantine of symptomatic subjects and close contacts of infected in hotels/dorms: Small children stay in the same private room as parents, and older children have their own rooms, each with their own bath rooms, to avoid cross-transmission.
Healthcare workers had a much higher risk of infection (3X) than general population when not protected by PPE before 2/1. The rate quickly dropped in the later periods with increasing awareness, wide use of PPE, proper training, adequate hospital-level prevention and management.
30,000+ health care workers (HCWs) from other provinces went to Wuhan to help care for patients. With comprehensive PPE, amazing that none of them was infected! Fully protecting HCWs in the outbreak of a high transmissible infectious disease is highly essential. They are heros!
Elderly people were at a higher risk of infection and were more likely to be severe/critical cases (RR=2.3 for 60-79 and RR=3.6 for 80+).
Children had a much lower risk of infection than adults, but the risk continued to increase over time when the rates in adults dropped after the interventions. Infants, however, had a much higher risk of infection compared with other children.
Increasing testing capacity is important to help with early diagnosis and treatment, prevent the deterioration of the patients, quickly isolate infected to block the transmission route.
In the shortage of testing capacity, priorities are given to high risk/vulnerable groups: HCWs, elderly, nursing home residents & workers, family members and close contacts of infected, essential workers, low income family, URMs, including those w/ mild symptoms and asymptomatic.
Contact tracing is important for identifying close contacts of infected so they can be quarantined.
The daily confirmed case rate per million people by gender, age and severity
The Geographic Distribution of Daily Rates of COVID-19 Cases Across the Five Periods in Wuhan
Thanks for the thoughtful editorial by @HartleyDM and @eliowa: "Taken as a whole, the study hints at a tantalizing possibility: the accessibility of data to support the real-time formative evaluation of public health interventions in an ongoing pandemic."
jamanetwork.com/journals/jama/…
jamanetwork.com/journals/jama/…
30,000+ health care workers (HCWs) from other provinces went to Wuhan to help care for patients. With comprehensive PPE, amazing that none of them was infected! Fully protecting HCWs in the outbreak of a high transmissible infectious disease is highly essential. They are heros!
Let real data & evidence speak:(1) Analyze real data & guide decision making based on real data analysis results, in addition to simulated data; (2) Replication of scientific findings using independent studies is important to ensure replicability & robustness of science findings
Effective public education and communication is critically important by sharing the gained scientific knowledge and information to the general public. This will help the general public make their own right decisions for themselves, loved ones and communities.
I was asked for a single take home message: Unite the community and everyone is a team member, contributes & works together for fighting for COVID-19: A multi-stakeholder approach by engaging our government, international organizations, academia, business, community & citizens
