Every week, we will address some common COVID-19 questions with evidence-based answers.
(Please note that these FAQs are created for the purpose of reducing confusion around COVID-19 misinformation, and are based on the current evidence at the time of posting. They should not be construed as advice or as a substitute for consulting a physician. Although we will strive to update these FAQs as answers may change over time, please do refer to the original source listed below for any changes to the evidence. See also our full disclaimer.):
Q: I heard COVID-19 can affect animals too. Are my pets at risk?
Question added: June 26, 2020
The World Health Organization has reported positive cases of COVID-19 in cats and dogs who were in close contact with humans infected with COVID-19. While the World Organization for Animal Health and several other veterinary associations state that there is currently no evidence that COVID-19 may spread from pets to humans, they do advise that pets are at risk for contracting the disease if they are in close contact with infected humans. Though these cases are rare, they recommend that people infected with COVID-19 minimize contact with their pets whenever possible.
(Source: iHealthFacts - Do pets spread COVID-19?)
Q: Now that summer is here, are my chances of contracting COVID-19 reduced? I heard that sunlight and warm weather can reduce the spread of COVID-19.
Question added: June 19, 2020
There are claims on social media that hot or humid weather can reduce the risk of contracting COVID-19. However, there is little conclusive evidence that sunlight or warmer weather can prevent or treat COVID-19. The WHO states that even countries with hot/humid weather have reported cases of COVID-19. Though there are some recent studies that suggest that weather conditions may influence the transmission of COVID-19, with cool and dry conditions appearing to boost the spread, the impact of weather is still considered minimal by experts. It's also important to keep in mind that other preventative measures, including physical distancing and handwashing, have also contributed to slowing down the transmission rate.
(Source: iHealthFacts - Can sunlight prevent or treat COVID-19?; Is the transmission of COVID-19 effected by hot or humid weather? and CEBM - Do weather conditions influence the transmission of the coronavirus (SARS-CoV-2)?)
Q: Does smoking prevent or lessen symptoms of COVID-19? I heard studies found that nicotine may protect against COVID-19 infection.
Question added: June 12, 2020
In late April, a French study investigating the role of nicotine in blocking the SARS-CoV-2 pathway caused speculation on social media that smoking may be used to prevent or lessen the symptoms of COVID-19. Irrespective of COVID-19, smoking can worsen the severity of respiratory diseases by impairing lung function, and the Chief Public Health Officer of Canada warns that smokers are a high-risk population for COVID-19. Though there are biologically plausible pathways where nicotine may impact the novel coronavirus, the WHO strongly recommends against tobacco smoking. While there are ongoing studies investigating the link between COVID-19 treatments and nicotine (which may be used in forms outside of cigarettes), the evidence is still extremely limited.
(Source: iHealthFacts - Can smoking prevent infection or lessen the symptoms of COVID-19? and CEBM - The role of nicotine in COVID-19 infection)
Q: Can you get COVID-19 if you've been infected before?
Question added: June 5, 2020
There is currently a lack of conclusive evidence indicating that the presence of antibodies (molecules made by our immune system in response to viruses) developed from a COVID-19 infection may provide immunity to re-infection of the novel coronavirus. In other words, even if you already had COVID-19, you may still be susceptible to getting the virus again. While there are studies testing for SARS-CoV-2 antibodies (the antibodies developed after COVID-19 infection), these studies are not designed to determine immunity to re-infection.
(Source: iHealthFacts - If I've already had COVID-19 am I immune to re-infection?)
Q: Every day there seem to be new symptoms of COVID-19. Is it true that loss of taste and smell are symptoms of COVID-19?
Question added: May 29, 2020
While less common than fever, cough, and fatigue, evidence has emerged since late February that indicates loss of taste and/or smell are indeed reported symptoms in people with COVID-19. As such, many government agencies including the UK and the US have recently listed loss of taste and smell as symptoms of COVID-19 that should warn individuals to self-isolate. Do keep in mind, however, that much of the current evidence on these symptoms is of poor quality, and ongoing studies using symptom tracking are required to increase certainty. As it stands, loss of taste and smell also frequently occur with the common cold and other influenza and so there will likely be many who display these symptoms without having COVID-19.
Q: Does the BCG (tuberculosis) vaccine prevent or lessen the symptoms of COVID-19?
Question added: May 22, 2020
The BCG vaccine is the most commonly used vaccine against tuberculosis worldwide. Myths have circulated that the BCG vaccine may protect against COVID-19, as there is a lower frequency of COVID-19 cases and mortalities in developing countries with universal BCG vaccination policies. There is evidence that BCG vaccination may prevent respiratory infections like pneumonia and influenza in children and the elderly. However, there is a lack of evidence that the BCG vaccine protects against COVID-19. More studies are currently underway.
(Source: CEBM - Does BCG vaccination protect against acute respiratory infections and COVID-19? A rapid review of current evidence and iHealthFacts - Does the BCG (tuberculosis) Vaccine prevent infection or lessen the symptoms of COVID-19?; Image source: Syringe and Vaccine, by NIH (CC BY 2.0))
Q: Should I take some disinfectant to protect myself against COVID-19? I heard that it might be possible to kill the coronavirus by injection.
Question added: May 15, 2020
Bleach and other disinfectants may kill the coronavirus when sprayed on surfaces. There is NO evidence that injecting disinfectant prevents or treats COVID-19. Injecting, drinking, or inhaling bleach or any other disinfectant can be poisonous, and may result in brain injury, blood clots, kidney and liver damage, or even death. Bleach and disinfectant should be used carefully to disinfect surfaces only.
(Source: iHealthFacts - Does injecting disinfectant prevent or cure COVID-19) | Image source)
Q: Can vitamin C prevent or cure COVID-19? I heard some hospitals were treating patients with high doses of the vitamin.
Question added: May 8, 2020
Vitamin C is an essential nutrient that is naturally found in some vegetables and fruits, particularly oranges and other citrus fruits. While some individuals treat the common cold with vitamin C, there is little evidence to support its efficacy. There is currently no evidence that vitamin C is effective in the prevention or treatment of COVID-19. High doses especially may cause stomach upset and diarrhea. However, more research is underway to study the effects of using large doses of vitamin C to treat COVID-19, including a Canadian trial.
(Source: iHealthfacts - Can large doses of vitamin C prevent or treat COVID-19?)
Q: Does taking vitamin D supplements prevent COVID-19? I heard people with vitamin D deficiencies have more severe COVID-19 symptoms.
Question added: May 1, 2020; updated May 7, 2020
Vitamin D is produced naturally when you are exposed to sunlight. While there is some evidence that points to vitamin D in helping to protect against respiratory tract infections, there are only clinical trials still being undertaken to see if vitamin D has a role in COVID-19 prevention or treatment. There is currently no reliable evidence that vitamin D supplements can be used to prevent or treat symptoms of COVID-19.
However, as many are staying indoors adhering to public health guidance, vitamin D levels may be lower than usual. As such, if a person cannot reach healthy levels of vitamin D through sun exposure and/or a healthy diet, some governments advise taking (no more than) the recommended levels of vitamin D supplements.
(Source: iHealthfacts - Does taking Vitamin D prevent or treat COVID-19? and CEBM - Vitamin D: A rapid review of the evidence for treatment or prevention in COVID-19; photo source: image by DarkWorkX from Pixabay)
Q: I heard that Advil (ibuprofen) worsens COVID-19 symptoms - is this true?
Question added: April 22, 2020
There is currently no conclusive evidence that NSAIDs including ibuprofen leads to a worsening of symptoms of COVID-19. However, until there is more evidence, some health organizations (such as the UK's NICE) recommend that people with confirmed or suspected COVID-19 take Tylenol (paracetamol) in preference to Advil (ibuprofen).
(Source: iHealthfacts - Does taking ibuprofen make the symptoms of COVID-19 (coronavirus disease) worse? and CEBM - NSAIDs in Acute Respiratory Infection)
Q: Should I take hydroxychloroquine (aka Plaquenil)? I heard it's a miracle drug to prevent and treat COVID-19.
Question added: April 17, 2020
Hydroxychloroquine is commonly used to treat malaria, lupus, and rheumatoid arthritis. Current data (as of Apr 14, 2020) does not support the use of hydroxychloroquine for the prevention or treatment of even mild cases of COVID-19. More studies are currently underway.
With new information and research developing daily about this virus, medical misinformation is being spread equally rapidly. Consider consulting one of these sources to verify news stories and rumours:
Sources include Full Fact (UK's independent fact-checking charity), FactCheck.org (A project of the Annenberg Public Policy Center, University of Pennsylvania), and Snopes.com
Search for topics in a database that gathers all of the falsehoods that have been detected by the CoronaVirusFacts/DatosCoronaVirus alliance. This database unites more than 100 fact-checkers in 45 countries and includes articles published in at least 15 languages.
A part of AFP's global news agency, this fact checker site has an international team of fact check reporters with expertise in digital verification monitor online content in multiple languages. Also part of Facebook's third-party fact-checking program.
Use their search engine to quickly and easily check the reliability of a health claim, verified against the current scientific literature.
Videos and handouts on health literacy. Includes resources in English & Spanish.
Provides a closer examination of the scientific validity of health research reported in the news.
Provides fact checks of Internet rumours and stories. Use this site to check the validity of that Facebook post shared by a relative about sipping garlic water to fight the coronavirus.
Try out this site's AI fake news detector by pasting the text of the news article in question.
Find out who the 'super-spreaders' of COVID-19 misinformation are with this free browser extension. During the pandemic, this browser extension is free (till Jul 1, 2020), and applies credibility scores to web browser search results and social media posts to help readers know which sites are reliable.
Offers unbiased and comprehensive answers to commonly asked questions surrounding COVID-19 including how to safely handle take-out and what "COVID toes" are. Also provides answers to common questions that have arisen from the news, such as if cases will surge due to protests, or what the latest news on the use of hydroxychloroquine is. Updated daily.
For more tips, please see this U of T Libraries guide on "How do I Spot Fake News?".
Struggling to understand COVID-19 data? Check out these resources to make better sense of the numbers behind the headlines.
For more help with understanding data visualizations and further develop your data literacy, please check out this data viz guide by the UofT Map & Data Library.
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