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Answers to 10 questions your patients have been asking about COVID-19

Misinformation about COVID-19 is spreading across social media at an alarming speed, prompting patients to turn to their doctors with many clinical questions. With new evidence coming out every day, knowing how to answer these questions with confidence can be a challenge.

Members of the DynaMed editorial team pulled together some evidence-based answers to ten questions patients are asking about COVID-19:


1. How common is it to have COVID-19 and not know it (i.e. be asymptomatic)?

Without universal screening, it’s hard to know how many people are infected and don’t know it. There have been some studies attempting to estimate the number of people with SARS-CoV-2 infection who remain asymptomatic. A recent systematic review estimated that 20 percent of people with SARS-CoV-2 infection never developed symptoms. Since people can test positive for COVID-19 before developing symptoms (during a pre-symptomatic period), even those who do not have symptoms at the time of diagnosis may not remain asymptomatic over time.


2. Can asymptomatic or pre-symptomatic patients spread the virus to others?

Yes, it appears so. Epidemiologic studies have shown that people with COVID-19 who are asymptomatic transmit the SARS-CoV-2 virus just as well as those who develop symptoms. This is one of the reasons why cloth face coverings and physical distancing measures have proven to be effective; they help reduce spread by people who don’t know they are infected.


3. I have been identified as a close contact of a known COVID-19 case. Why do I need to quarantine if my nose test was negative?

Viral testing using a nasal swab looks for genetic material from SARS-CoV-2, which is detectable only during a certain window after infection. The incubation period for the virus is up to 14 days. So, if you have a negative test within the first few days after exposure, you could have a positive test a few days later. That’s because it can take up to 14 days for the virus to become detectable. That is why everyone with a known exposure should quarantine for 14 days, even if viral testing is negative. 


4. Should I get an antibody test to see if I’m immune?

An antibody test works by indicating whether or not your body has made an immune response against the SARS-CoV-2 virus. It’s unclear at this time whether a positive antibody test truly means you’re immune (i.e. safe from infection or reinfection). Either way, there is a small chance of a false positive test due to antibodies generated against seasonal coronavirus infections. Even those with a positive antibody test should continue to take measures to protect themselves and others.


5. How can you tell the difference between the flu and COVID-19?

Influenza virus and SARS-CoV-2 are both contagious respiratory pathogens that cause illnesses ranging from a mild upper respiratory tract infection to severe pneumonia, and both can be fatal. Testing is the only way to distinguish between them because the symptoms of flu and COVID-19 can be similar. This flu season, patients with flu-like symptoms should be tested for both influenza and SARS-CoV-2 viruses in addition to other respiratory pathogens, if indicated by other clinical and epidemiological factors.


6. What is remdesivir and who should get it?

Remdesivir is an antiviral agent that works to block the replication of the SARS-CoV-2 virus, and is authorized for use in hospitalized patients with severe COVID-19. Notably, the World Health Organization has discouraged its use because it hasn’t been shown to improve survival. Remdesivir has also been recommended in combination with corticosteroids, though there is no clinical trial data to evaluate this regimen at this time.


7. What is this new bam-mab drug?

A new therapy called bamlanivimab has recently received emergency use authorization from the United States FDA and is currently being evaluated by the Public Health Agency of Canada (PHAC). It was engineered in a lab based on an antibody that was identified in one of the first patients to recover from COVID-19 in the United States.

Bamlanivimab is an antibody that targets the SARS-CoV-2 spike protein and blocks it from infecting cells. It’s a monoclonal antibody, meaning it has a single target on the virus — this is unlike the human body’s response, which targets many parts of the virus. In a randomized trial, bamlanivimab reduced the amount of SARS-CoV-2 virus in patients with mild-moderate COVID-19. It remains unclear whether it reduces disease severity or duration, and trials evaluating bamlanivimab and other monoclonal antibodies are ongoing.


8. If I have COVID-19, how long will my symptoms last?

It’s clear now that some patients with COVID-19 experience symptoms beyond what we would consider the acute phase of the infection. These patients aren’t always the most severely affected either; a cohort study estimated that about one-third of patients with mild COVID-19 who did not require hospitalization had symptoms two to three weeks after their diagnosis. Cough and fatigue were the most common lingering symptoms in these patients.


9. If I have COVID-19, when can I be around others again?

If you have COVID-19 and do not require hospitalization, you should isolate yourself and avoid contact with other people whether you have symptoms or not. You should remain in isolation for at least 10 days and until your health care provider or Public Health Authority deems you are no longer at risk of spreading the virus to others.  


10. What are the chances of getting COVID-19 twice?

Though it appears to be rare, there have been a few reports of reinfection. We are learning more about the immune response to the SARS-CoV-2 virus every day, but it’s still unclear whether everyone develops protective immunity after infection. People who have had COVID-19 should continue physical distancing and mask wearing after hospitalization and/or isolation. 


For more information, see the topic COVID-19 (Novel Coronavirus) in DynaMed


Original article published on EBSCO Health Notes. Written by:

  • Vito Iacoviello, MD, Deputy Editor for Infectious Disease, Allergy, and Immunology at DynaMed; and
  • Heather D. Marshall, PhD, Senior Medical Writer in Infectious Disease, Allergy, and Immunology and Digital Media Specialist at DynaMed.


Do you have a question on COVID-19 or another clinical topic? Contact the Ask a Librarian team to request a literature search.


This material is for informational purposes only. It is not intended to be a substitute for professional medical advice and should not be relied on as health or personal advice. The opinions stated by the authors are made in a personal capacity and do not necessarily reflect those of the Canadian Medical Association and its subsidiaries including Joule. 

About the author(s)

DynaMed is a clinician-focused tool designed to facilitate efficient and evidence-based patient care. Rigorous, daily review of medical literature by physician and specialist staff ensures timely and objective analysis, synthesis and guidance. DynaMed includes drug content from Micromedex, Canadian and international guidelines, and clinical images. CMA members have access to DynaMed, a point-of-care tool, included with their membership ― a tool valued at US$399 a year.