It’s impossible to read about the COVID-19 coronavirus without running into a few dangerous myths.
But some of these myths can be deadly. So let’s explore three COVID-19 myths to learn about the most widely spread rumours.
Myth: Asymptomatic people can’t spread the coronavirus
The idea of the “silent spread” of COVID-19 – that asymptomatic people can spread the coronavirus – has spread like wildfire.
After some confusion, the World Health Organisation (WHO) clarified that most documented cases of “asymptomatic” spread actually turned out to be cases in which the person was presymptomatic and later developed mild or severe symptoms. Therefore, the WHO acknowledged that asymptomatic people can play a role in spreading COVID-19.1
It’s also important to acknowledge that the term “asymptomatic” as used in everyday conversations can actually have three different scientific meanings:
- When you’re asymptomatic, you are carrying the virus but show no symptoms. However, you are still able to infect others.
- When you’re presymptomatic, you have recently contracted the virus and have yet to show symptoms and are also asymptomatic. You are still able to infect others at this stage of infection and will begin to show mild or severe symptoms.
- When you are mildly symptomatic, you do not experience pneumonia associated with COVID-19, but rather mild coronavirus symptoms. You belong to the most infectious types of spreaders, as it is highly likely that you’re out and about.
And several extensive studies suggest that cases of asymptomatic people that test positive for COVID-19 often turn out to be presymptomatic.2,3,4 However, all of these “asymptomatic” types of spreaders should be taken seriously.
According to the WHO, there are three primary ways that you can catch COVID-19:
- being coughed or sneezed on by someone with an active infection and symptoms5
- touching a surface that carries infected respiratory droplets and then touching your face (eyes, nose, or mouth)6,7
- being in enclosed spaces where infected airborne particles can build up
You can transmit the virus with only one mild cough or sneeze containing infected droplets. It’s easy to forget about such a mild symptom and think you never had symptoms at all. But one cough or sneeze is enough to infect others.
Research also suggests that, in confined spaces over prolonged periods of time, COVID-19 can be spread when you sing, yell, or even talk because infected droplets and aerosols from your mouth can hang in the air indefinitely, exposing people nearby to infection even when you’re asymptomatic, presymptomatic or mildly symptomatic.8
But you don’t have to get into the semantics of deciding if someone is asymptomatic, presymptomatic, or mildly symptomatic, as our obsession with semantics could have a deadly impact.
And that’s why it’s so essential to follow prevention protocols, which can reduce your risk of contracting COVID-19 to nearly zero:
- Maintain two metres of social distance at all times.
- Wear a protective face covering.
- Wash your hands for 20 seconds throughout the day.
- Don’t share any utensils.
Following these easy steps will help keep us safe.
Myth: Pets can’t spread the coronavirus
The short explanation is that pet dogs and cats could get COVID-19 from humans and carry and spread the virus to other humans and animals.9
It’s worth noting that animals are thought to be the sources of all coronaviruses.
Although it is rare, scientists suspect the source of COVID-19 was a coronavirus that spread from an animal to a human at a wet market. This was the case with both SARS and MERS. In fact, scientists hypothesize that bats and pangolins are the likely source of COVID-19.10
There’s not a lot of research showing exactly how your pets respond to when exposed to the coronavirus. But we do know that animals can get it from humans and spread it.11 Regarding COVID-19, it’s important to treat a pet like any other member of your family and take precautions to stop COVID-19 to flatten the curve.12
For example, if you have a COVID-19 infection, you can potentially infect your dog with the virus by coughing or sneezing on them. Then, your infected dog, while sitting on your father’s lap, can then cough or sneeze, thus infecting your father by spreading the virus through mucous membranes.
So to be on the safe side, pet owners should socially distance their pets too. Don’t let strangers touch your pets while you’re outdoors. Infectious droplets could get into your pet’s mucous membranes or reach their face or paws from other pets.
And if you see someone else’s dog or cat, don’t pet them.
Cats may be especially problematic when it comes to COVID-19, since cats have a protein receptor called ACE2 that’s very similar to one in humans that the coronavirus latches onto.13
This means that cats might be as likely as humans to become infected with COVID-19 from infected respiratory droplets or transmission through the eyes, nose, and mouth.
So here’s what you should do to protect your pets and your household:
- Keep your pets away from infected family members and from other people or their animals outside your home.
- Don’t let your cats or dogs wander outside beyond your home.
- Put dogs on a leash at all times outside the house, keeping them 2 metres away from people and animals.
- Don’t take your pets to places where large groups gather, such as dog parks or indoor pet playgrounds.
Myth: All masks provide equal protection from the coronavirus
Different masks provide different levels of protection from COVID-19.
Most localities and public health organisations have recommended wearing a simple cloth face covering in public. This will help protect you from large, infectious respiratory droplets.14,15,16,17,18
But face coverings like cloth masks, bandanas, or gaiters provide limited protection from airborne aerosols in crowded places when social distancing is impossible.19,20,21,22
Although cloth masks offer limited protection to the wearer, cloths masks are an effective strategy as a collective public effort – as long as everyone wears them. The fewer people that wear them, the less likely it is that this collective public effort will be effective.
There are higher quality masks that offer the wearer a higher level of protection. A certified N95, FFP2, or KN95 respirator mask is designed to protect the wearer.23 These are the only types of masks that provide high levels of personal protection from COVID-19.
In hospital settings, airborne aerosols that contain the coronavirus can build up to high concentrations in spaces where patients are in close quarters with medical staff.24
Worn properly, medical-grade respirator masks filter out most infectious aerosols and ensure that the air that the wearer breathes is virtually free of aerosolized viruses.25
Considering the higher effectiveness of N95, FFP2 or KN95 masks, it also makes sense that individuals, especially those who are at higher risk for severe illness, also benefit from higher levels of personal protection.
To learn more about face masks, see our piece Face masks 101: Infection control.
Ask your doctor or a medical professional for the most accurate prevention and treatment information – and pay close attention to trusted sources of health news and information who use rigorous research and science to back up their claims.
IQAir is a Swiss-based air quality technology company that since 1963 empowers individuals, organizations and communities to breathe cleaner air through information, collaboration and technology solutions.
 Joseph A. (2020, June 9). ‘We don’t actually have that answer yet’: WHO clarifies comments on asymptomatic spread of Covid-19.
 Wong J, et al. (2020). High proportion of asymptomatic and pre-symptomatic COVID-19 infections in travelers and returning residents to Brunei. DOI:
 Wenjing G, et al. (2020). 新型冠状病毒肺炎潜伏期或隐性感染者传播研究进展. DOI: 10.3760/cma.j.cn112338-20200228-00207
 Arons MM, et al. (2020). Presymptomatic SARS-CoV-2 infections and transmission in a skilled nursing facility. DOI: 10.1056/NEJMoa2008457
 COVID-19 virtual press conference – 8 June 2020. (2020).
 Van Doremalen N, et al. (2020). Aerosol and surface stability of SARS-CoV-2 as compared with SARS-CoV-1. DOI: 10.1056/NEJMc2004973
 Furukawa NW, et al. (2020). Evidence supporting transmission of severe acute respiratory syndrome coronavirus 2 while presymptomatic or asymptomatic. DOI: 10.3201/eid2607.201595
 Liu Y, et al. (2020). Aerodynamic analysis of SARS-CoV-2 in two Wuhan hospitals. DOI: 10.1038/s41586-020-2271-3
 Can dogs get coronavirus? (2020).
 Li X, et al. (2020). Emergency of SARS-CoV-2 through recombination and strong purifying selection. DOI: 10.1126/sciadv.abb9153
 Can I catch COVID-19 from my pet or other animals? (2020).
 Helpful questions and answers about coronavirus (COVID-19) and your pets. (2020).
 Wan Y, et al. (2020). Receptor recognition by the novel coronavirus from Wuhan: An analysis based on decade-long structural studies of SARS coronavirus. DOI: 10.1128/JVI.00127-20
 Gilbert ES. (2009). Ionizing radiation and cancer risks: What have we learned from epidemiology? DOI: 10.1080/09553000902883836
 Coronavirus disease (COVID-19) advice for the public: When and how to use masks. (2020).
 COVID-19 frequently asked questions. (2020).
 Zhang R, et al. (2020). Identifying airborne transmission as the dominant route for the spread of COVID-19. DOI: 10.1073/pnas.2009637117
 Van der Sande M, et al. (2008). Professional and home-made face masks reduce exposure to respiratory infections among the general population. DOI: 10.1371/journal.pone.0002618
 Mayo Clinic Staff. (2020). COVID-19: How much protection do face masks offer?
 Viola IM, et al. (2020). Face coverings, aerosol dispersion and mitigation of virus transmission risk.
 Konda A, et al. (2020). Correction to aerosol filtration efficiency of common fabrics used in respiratory cloth masks. DOI: 10.1021/acsnano.0c04676
 Konda A, et al. (2020). Aerosol filtration efficiency of common fabrics used in respiratory cloth masks. DOI: 10.1021/acsnano.0c03252
 Gralton J, et al. (2010). Protecting healthcare workers from pandemic influenza: N95 or surgical masks? DOI: 10.1097/ccm.0b013e3181b9e8b3
 Jayaweera M, et al. (2020). Transmission of COVID-19 virus by droplets and aerosols: A critical review on the unresolved dichotomy. DOI: 10.1016/j.envres.2020.109819
 Bessesen MT, et al. (2013). N95 respirators or surgical masks to protect healthcare workers against respiratory infections: Are we there yet? DOI: 10.1164/rccm.201303-0581ED