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Q&A with Dr Wenhong Zhang on 3/30/20

Dr. Zhang is the Director of Department of Infectious Diseases, Huashan Hospital, Fudan University, and the leading physician in the COVID-19 expert team in Shanghai 

For full article, see here.

Q1: What is the time window between infection and testing positive?

A: PCR test will usually turn positive under 2-3 days after the infection. Serological test i.e. antibody- based test (IgM) would mostly turn positive in 8-10 days after the disease onset. Viral load is the highest during the first week of disease onset and would decrease later.


Q2: For the general public, what are the criteria to request a SARS-CoV-2 test? For healthcare workers?


A: In Shanghai, people who meet at least one of the epidemiological criteria and one of the clinical criteria should request a test. Originally, only people who returned from Wuhan and Hubei province would meet the epidemiological criteria. Now people with travel history to any countries/regions with local transmission cases meet the epidemiological criteria. People should also request a test if they have close contact with confirmed patients or if clustered cases were observed around them. Clinical criteria include symptoms such as coughing, fever and diarrhea. We try to test every suspected case in Shanghai and this is the key to closely monitoring the epidemic trend. All tests are provided free of charge.


Q3: What are the pros and cons of PCR-based test Vs antibody-based test?


A: PCR test is the gold standard. We are still gaining more experiences concerning antibody-based tests in Shanghai. Currently, antibody-based test can serve as a complementary test to the PCR test. It might work better after 8-10 days of disease onset because the viral load might be too low to be detected by PCR test (false negative) in the later stage. Antibody tests could also be a useful tool to understand the epidemic trend for a large population.

Q4: How to prevent viral RNA degradation during sample processing?


A: The sample should be processed as soon as possible (usually within 4-6 hours), and if not, sample should be stored at -20C/-80C.


Q5: For people who are self-quarantined for 14 days at home, should they be tested? If yes, when and how frequent?


A: If no symptom was observed after quarantine, no test is needed.


Q6: What is the risk of getting infected for pregnant women and infants compared to other demographic groups? If infected, what are the treatment options?


A: Not many cases of pregnant women and infants were reported in Shanghai. Only 50-60 children were treated and they all have mild symptoms. No anti-viral treatment was used on children in Shanghai. No severe cases for pregnant women, infant and children observed in Shanghai.


Q7: From mild to severe symptoms, how long will it take?


A: Usually 8-9 days.

Q8: Why people with underlying medical conditions are at high risk? Young age but with underlying conditions are also at high risk?

A: Young people with underlying medical conditions are also at high risk. People with heart disease have the highest risk.

Q9: At large population level, do you observe the attenuation of the infectivity or pathogenicity of SARS-CoV-2 over time?

A: Not observed so far. The number of severe cases has decreased but there’s probably no attenuation of the infectivity of the virus. 


Q10: Ibuprofen VS acetaminophen, which one is better to treat fever at home for mild COVID-19 patient?


A: Acetaminophen is recommended because of fewer side effects.


Q11: Literature reported that ARB inhibitor like Losartan can increase cell surface ACE2 expression. Do you observe people who are taking ARBi showing a higher chance of SARS-CoV-2 infection? How about use Losartan to reduce lung inflammation in COVID-19?


A: We did not observe people who are taking ARBi showing a higher chance of SARS-CoV-2 infection. ARBi losartan has not shown effect in reducing lung inflammation in SARS-Cov-2 cases.


Q12: What is the percentage of recovered patients showing detectable neutralizing antibodies against SARS-CoV-2? What type of antibodies? What is the efficacy against COVID-19?


A: Antibodies were detected in all recovered patients. It’s still hard to say if they have efficacy or not. It also depends on the type of antibody produced.


Q13: Will upcoming summer slowdown global pandemic of COVID-19?


A: Summer might help a little bit, as the activity of the virus has shown to decrease with the temperature rising. However, this phenomenon was mostly observed in the laboratory, and the temperature would need to be as high as around 60℃ to kill the virus. Therefore, the summer might slow down the transmission in the northern hemisphere to some extent, but we still need to remember the risks of epidemics in the southern hemisphere will not diminish by that time. COVID-19 might not be eliminated this year. It might reappear in the winter. The coming 2-3 months is critical for US to take actions to slowdown the spread of the disease.


Q14: Can hydroxychloroquine help to prevent COVID-19? Dose and side effects?


A: Data currently available is controversial. However, it’s probably OK for medical personnel and family members to take hydroxychloroquine under strong cautions to prevent COVID-19, as long as no significant side effect is observed.


Q16: How to use hydroxychloroquine for COVID-19 treatment? Dose and frequency?


A: The dosage we used was day 1: 400mg b.i.d., day 2 and after: 400mg q.d. Only monotherapy has been used. We are worried about liver injury caused by the combination therapy with azithromycin, and that’s why we have not tried the combination of hydroxychloroquine and azithromycin. We have not tried the hydroxychloroquine and zinc combination either.


Q18: How important it is to cover head/neck/shoes when treating COVID patients? 


A: Covering the head is the most important.


Q19: How often are HCWs infected from the virus?


A: Only HCW in Wuhan without proper PPE at the beginning of the outbreak were infected. None of the HCW in Shanghai or HCW sent to Wuhan

from Shanghai with proper PPE was infected.


Q20: Is regular surgical mask adequate for HCWs to prevent COVID-19 under mild patient and severe patient?

A: No. N95 is required. PPE is very important.


Q21: Are you routinely testing healthcare workers who are exposed to COVID+ patients?


A: In Huashan hospital we test HCWs. However, it’s probably not necessary to do the test if people wear proper PPE and no symptom is observed.


Q22: Can COVID-19 be transmitted by air droplet/airborne, in closed spaces, such as elevator, waiting room?


A: Air droplet would impose a risk to people without proper PPE (masks). However, in our hospital no patient was infected via air droplet in the elevator or fever clinics. Only close contact with an infected person would transmit the disease.


Q23: At US, healthcare workers go home after work. What procedure need to be done to prevent spreading the virus to family members?


A: Healthcare workers at Shanghai Public Health Clinical Center would stay at the hospital. Those who work at the Shanghai Children’s Hospital do go home every day. They wear proper PPE, take bath and wash face and nose frequently. In addition, they do not have dinner together with their family members.


Q24: For hospital departments that do not directly interact with COVID-19 patients, can healthcare workers use reduced PPE?


A: No.


Q25: For healthcare workers that interact with COVID-19 patients, what need to be done before eating and drinking?


A: Proper PPE is required, and frequent cleaning of face and nose is recommended.


Q26: What is the procedure to discharge COVID-19 recovered patients? Do they need to self-quarantine at home for 14-days?Is there a possibility of viral rebound?


A: The patient can be discharged if tested negative by PCR test twice. After discharge, we require the patient to be quarantined at home for 14 days.


Q27: If a patient survived severe COVID-19, will his/her lung surfer long term injury? Fibrosis?


A: Unlike SARS patients, most severe COVID-19 patients fully recovered in less than two weeks. They are all in good conditions with no or minimal fibrosis.


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