We know you have questions. Here’s the answers- scientific but simplified.


This will be updated to reflect the most up-to-date research.

Numbers in brackets indicate the information came from a specific paper in the references section.

A. Bacteria VS Viruses

1.What’s the difference between bacteria and viruses?(18)

The main difference between bacteria and viruses is that bacteria can divide on their own! If a human cell is like a major city, a bacteria is a small town: it doesn’t have all the components and ‘amenities’ of the bigger human cell but it still does the same basic functions. Bacteria grow and reproduce and can copy their own DNA. They have their own biochemical processes and DNA replication machinery. Antibiotics work against bacteria, mainly by targeting aspects of the bacterial DNA replication machinery and preventing the bacteria from reproducing. Not all bacteria are bad and there are plenty of them living in your body right now. When bacteria are pathogenic, they can cause infection and severe diseases including cholera, tuberculosis and (famously) the Black Plague. A lot of bacterial diseases are either eradicated or lessened in severity thanks to antibiotics.

If a human cell is a city and a bacterial cell is a town, a virus is a floating message in a bottle. Viruses are typically enveloped or non-enveloped. What this means is that some viruses have a lipid membrane around their central ‘core’ and some don’t. Either way, every virus has a capsid (the bottle) and a genome (the message). Viruses can infect bacteria or animal cells. They work by breaking into the membrane of the cell they’re infecting and forcing the cell’s machinery to ‘read’ the ‘message’, which makes more virus DNA and more viruses. When these new viruses break out of the cell they infected, they destroy it. Viruses can cause diseases such as the common flu, HIV, measles and rubella. They can often be treated with anti-viral drugs, but not all anti-virals work against all viruses.

For a really good video on this topic, check this out!


2. If I have a virus, can I take antibiotics for it? 

Antibiotics DO NOT work on viruses, and in fact overusing antibiotics (by trying to use them to treat viral sicknesses) can lead to antibiotics becoming less effective against diseases caused by bacteria. Always follow your healthcare practitioner’s advice on the best course of action for a disease treatment and do not self medicate or use old medications.


3. Are there vaccines against bacteria and viruses?

Both bacterial and viral diseases can be vaccinated against. A vaccine is used to train your body’s natural shock troopers- the immune system- in case of future attacks by a particular disease. When you’re vaccinated, your immune system is taught what to expect and is ready to raise the alarm at the slightest sign of a future infection.

See the CDC’s information on vaccines here.


4. How long does a vaccine take to make?

From research to trials to approval, making a vaccine is a very long process. First researchers in a lab have to make sure they have something that is scientifically sound. Then the vaccine has to pass many rigorous trials. Then it has to be approved for human use. This is a very long process and can take several years, although scientists place the current estimates around 12-18 months in a best case scenario(19).

B. nCoV-19 vocabulary

5. “Coronavirus,” nCov-19 and COVID-19 are often used interchangeably, but there are some subtle differences(1):

“Coronavirus” is a type of virus. Coronaviruses are enveloped (they have a lipid membrane), use positive-sense RNA and display club-like protein spikes on their surfaces. These viruses typically have an unusually large RNA genome and can be identified by their unique replication strategy. The novel coronavirus is part of a specific type of coronaviruses, the β-coronavirus cluster, which also includes SARS (SARS-CoV) and MERS.

nCoV-19, also known as SARS-CoV-2 (Severe acute respiratory syndrome coronavirus 2) is the name assigned to the 2019 novel coronavirus responsible for the current outbreak. SARS-CoV-2 should not be confused for SARS-CoV, which is the virus responsible for the SARS outbreak in 2002-2003.

COVID-19 is the name given to the disease that arises following infection with nCoV-19. Symptoms of COVID-19 include fever, cough and shortness of breath.

C. nCoV-19 biology

6. What does ‘enveloped virus’ mean? (2)

nCoV-19 is an enveloped virus, which means that it has a lipid membrane surrounding a protein core. A lipid is kind of like fat and the molecules that make up the membrane of nCoV-19 are a special class of lipids called amphipathic lipids. The word amphipathic means that these molecules have a part that is water-loving and a part that is water-hating. nCoV-19 uses positive-sense RNA to code its genome.

7. I keep seeing that SARS-CoV-2 is a ‘positive-sense, single stranded RNA virus.’ What does this mean? (20)

‘Positive-sense, single stranded RNA’, or +ssRNA, is a way of describing how the virus carries its genetic material. The genetic material of a virus is its instruction manual, the step-by-step guide to make more viruses once this one manages to sneak into a cell. These instruction manuals can come in many shapes and forms. Viruses can use DNA or RNA for their genomes. The DNA or RNA used by a virus can also be single stranded or double stranded. If double stranded DNA or RNA looks like a ladder, then a single strand looks like a ladder that’s been sawed in half lengthwise. 

SARS-CoV-2 uses RNA, which is why it’s a ‘RNA virus.’ The RNA it uses is single stranded, which is why it’s a ‘single-stranded RNA virus.’ Now what about this ‘positive-sense’ part? 

A positive sense RNA virus has RNA that is immediately ready to be fed into the cellular replication machinery to make proteins. It’s ready to go right off the bat. To contrast, negative sense RNA viruses have an instruction manual (RNA) that’s written almost in mirror image. The negative sense RNA viruses have to go through a translation process (‘what the heck does this say?’) before they can start using their RNA to make more viruses.

So to summarize:

Positive sense = RNA is ready to use right away

Single stranded = One RNA strand, not two

RNA = Uses RNA, not DNA

Therefore SARS-CoV-2 is a positive-sense, single stranded RNA virus.


8. How does nCoV-19 infect cells? (3)

We did a sidebar on this! Check it out here.

Earlier in this document viruses were referred to as ‘messages in a bottle.’ When the way a virus infects a cell is considered, it might be more appropriate to think of them as spies carrying a message. When a virus approaches the ‘city’ of a cell, it first has to sneak its way past the city walls, then release the message into the city and then use that message to make more spies, revolutionaries and allies for itself. nCoV-19 is no different. It attacks lung cells specifically and gets in by using a protein that acts as a ‘key’ to push the virus through the membrane of lung cells. This ‘key’ is called the S protein. When the S protein binds to the receptor (the lock) on the target cell, the infection begins. 

The receptor for the 2019 novel coronavirus is located on human lung cells. The virus binds to the receptor and uses that binding as a way to breach the cell membrane and expel its ‘message’ into the inside of the cell. Once the virus’ message has been released into the cell, it takes over the cellular machinery to make more copies of the virus. The binding of nCoV-19 to its receptor causes the cells to make more of the receptor. There is evidence that the increased amount of this receptor can lead to the respiratory distress associated with COVID-19


9. Will the pandemic die down as temperatures climb? 

In general lipid envelopes are sensitive to dehydration or disruption by temperature extremes, which could then lower the virus infectivity.(6) While some studies have indicated that viral transmission may go down in highly humid conditions(17),  other studies have concluded that humidity and higher heat may not have any impact on transmission. As things stand now, continued social distancing measures are very important- we can’t expect this to just go away as temperatures climb.

D. Safety Precautions

12. Can nCov-19 cause permanent lung damage?

COVID-19 can lead to ARDS (acute respiratory distress syndrome). In some cases of serious respiratory distress doctors have observed something called ground-glass opacity in the lungs, which indicates fluid in the lungs or thickening of the internal lining. In very severe cases of COVID19 infection the host inflammatory response can become a major cause of lung damage.(4) 


13. What are some risk factors for severe COVID-19 symptoms?

Risk factors for severe disease onset include being an older adult or having serious pre-existing medical conditions including heart or lung disease or diabetes.(5)


14. How long does it take for a person to show symptoms of COVID-19?

The typical incubation time (the amount of time between infection and symptoms beginning to show) for COVID-19 appears to be 5.2 days, with most infected individuals showing symptoms by the end of a 14 day period from exposure (9). That being said many individuals may be asymptomatic (not show symptoms) or present only mild, flu-like symptoms.  Some individuals can still be contagious even before they start showing symptoms. The safest thing to do is to self-isolate for 14 days if you think you were exposed to COVID-19. If you develop symptoms during those 14 days, your quarantine starts over. Symptoms of COVID-19 include fever, dry cough and shortness of breath (1).


15. If I show symptoms, how long am I contagious for?

Most people are infectious for an average of 20 days after symptoms show (minimum 8, maximum 37). If you show symptoms, isolate as directed by local healthcare practitioners but know that you can remain contagious for up to 40 days. (10)


16. Can COVID-19 spread through breastfeeding or be transmitted from mother to baby during pregnancy?

A recent study of six pregnant women who were sick with COVID19(17) at the time of delivery found that the infants did not contract the virus from their mothers. Interestingly the babies did have antibodies against the virus in their bloodstream, despite not actually being sick with the virus. It’s important to note that this particular study had a very small sample size and more research on this particular question is needed before a definite conclusion can be reached. It is also currently unknown whether the virus can be spread through breastmilk.

If you are pregnant and have COVID19, please adhere to the CDC’s guidance. This webpage has more details on what should be done by mothers carrying the virus in order to protect their infants.


16. Are children at risk from nCov-19?

The elderly and those with underlying medical conditions are most at risk for advanced complications. A recent study showed that children of all ages susceptible to COVID-19, but they generally showed less severe symptoms than adult patients. That being said, young children- especially infants- seem more at risk of infection.(7,8) 

The overall mortality rate in children and infants is significantly lower than in adults. However, it is unclear how underlying respiratory infections such as asthma may impact how the virus behaves in children.

Updated June 7, 2020: The CDC is monitoring cases of Multisystem Inflammatory Syndrome in Children (MIC-C) associated with COVID-19. Please see CDC guidance on MIC-C here. CDC guidance on children’s health-related to COVID19 can be found here.

It is very important to make sure that children also observe proper hand hygiene and social distancing.


17. Are soap and water really enough to kill the virus? How?

Yes! The number one precaution that can be taken against nCoV-19 is washing your hands with soap and hot water. As previously stated, this virus is sensitive to heat, which is why hot water is a major form of defence. However the true power in regular hand washing lies in the use of soap- any soap at all. It is not necessary to use special antibacterial soaps (antibacterial does not mean antiviral). Soaps, like amphipathic lipids, are amphipathic molecules (amphipathic means that these molecules have a part that is water-loving and a part that is water-hating). When soap molecules come in contact with the lipid membrane of the virus they have the effect of ripping the lipid membrane apart. Without this membrane the virus cannot display the ‘key’ that allows them to infect cells and the virus has therefore been inactivated. So the first measure that everyone can take is to regularly wash their hands with soap- ANY SOAP- and HOT water.

For more, see this amazing NYT article. We also did a sidebar on this, found here.


18. What substances have been shown to kill the virus? What do I use to clean surfaces?

The EPA has complied a list of cleaning agents that are effective inactivators (stops the virus from being infectious) of coronaviruses. This list was put together based on the virus biology as well as what has historically worked against viruses of the same family, including SARS and MERS. 

A study in the Journal of Hospital Infection also compiled known research (11).  Potential cleaning agents include:

  • Sodium hypochlorite (Bleach): 0.1%
  • Alcohol (ethyl or isopropyl/rubbing alcohol): 62-71%
  • Hydrogen peroxide: 0.5%

Please note the importance of contact time. Let the cleaning agent sit on the surface you wish to disinfect for a few seconds before wiping it off. Technically the virus should be inactivated quickly, but it is good practice to give the cleaning agent more time to work.

Also note that the effective concentration of alcohol is 62-71%. This means that most alcoholic drinks do not contain a sufficiently high concentration of ethanol to effectively kill the virus. Please also note that drinking isopropyl alcohol or research grade ethanol is highly dangerous and could lead to brain damage, permanent blindness, or death. 

While alcohol and alcohol based hand sanitizers have been proven to kill the virus, hand washing with soap and water is equally effective.

It’s also a good idea to remove items from the area surrounding sinks, because droplets from the sink can carry virus particles onto nearby objects. The counters around sinks should also be regularly wiped down with a diluted bleach solution (see above for percentage).  


19. How long can the virus survive outside of the human body?

If a person coughs and spreads saliva or mucous to a hard surface, the virus can live on that hard surface for some time(12), although estimates vary between 3 to 9 days. It is recommended that surfaces such as doorknobs, cupboard handles, counters, tables, etc are regularly wiped down with a cleaner (like the ones on the list above). Wash clothes regularly in the hottest possible water setting and dry them completely. Drying clothes in direct sunlight is an option when access to an electric clothes dryer is not available.  


20. How does the virus spread?

Main forms of transmission of the virus are through direct contact or respiratory droplets. Maintaining a distance of at least 6 feet from other people is a good start to prevent transmission. However regular hand washing is also important so that any virus particles that your hands pick up from surfaces don’t find their way into your body.

The major way for pathogens to enter your body is through the mucous membranes- including your nose and mouth, and through your eyes (13). Do not touch your face before washing your hands and also consider regularly washing your face with soap throughout the day.

Updated April 4, 2020: 

The CDC is now stating that several people can be either asymptomatic (infected but not showing symptoms) or presymptomatic (recently infected but not showing symptoms yet) and still spread the virus through speaking, coughing or sneezing. Wear a cloth face covering when out in public and maintain social distance. 


21. I see a lot of people wearing masks. Do they really help?

Updated April 4, 2020: The CDC is now recommending the use of cloth-face coverings in public, especially given the asymptomatic and presymptomatic transmission of nCoV-19 that has been observed. Masks may not protect against becoming infected, but can lower the risk of transmission.

Additionally many people have elected to wear either surgical or particulate (N-95) masks in public.

Surgical masks may provide protection against the virus, especially if you are taking care of someone currently sick. However, they can also be problematic. Adjusting a surgical mask is another way for a virus to jump from your hands to a mucous membrane. Additionally, virus-containing respiratory particles can still make their way through the gaps between the mask and your skin. If you do elect to wear a mask, please see WHO guidance on when and how to use masks here. Note their advice on how to take off masks safely as well.

N-95 masks provide better protection against the virus (when properly worn) than surgical masks. Medical professionals who regularly use N-95 masks have to be given proper training in order to properly adjust the mask so that all seals are adequate to provide true protection. If you elect to wear an N95 mask, make sure to look up how to properly adjust the seals. (14)

It is a good idea to wear a mask if you are coughing or sneezing, as directed by WHO. However wearing a mask is not enough to completely protect others from the virus. If you can- stay home. It is critical that we take any possible measures to limit the spread of COVID-19.

It’s important to note that masks are critical personal protective equipment for people with immune disorders, medical professionals and healthcare staff and shortages might impact the healthcare system as a whole. There are currently mask shortages in several countries which are made worse by stockpiling. According to CDC guidelines, cloth face coverings should be used when possible.


22. What do I do if I think I have COVID-19?

If you think you have COVID-19 and are not presenting severe symptoms, call your healthcare practitioner to inform them and follow their directions. The current recommendations are to stay home and away from other people. If you start to display warning signs, seek immediate medical attention. Warning signs include:

  • Difficulty breathing or shortness of breath
  • Persistent pain or pressure in the chest
  • New confusion
  • Bluish lips or face

If possible, have someone call ahead to inform the medical centre of your arrival and that a patient positive for COVID-19 is inbound.

See the CDC’s guidance for more information.

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  2. Rey, F. A., & Lok, S.-M. (2018). Common Features of Enveloped Viruses and Implications for Immunogen Design for Next-Generation Vaccines. Cell172(6), 1319–1334. doi: 10.1016/j.cell.2018.02.054
  3. Fehr, A. R., & Perlman, S. (2015). Coronaviruses: An Overview of Their Replication and Pathogenesis. Coronaviruses Methods in Molecular Biology, 1–23. doi: 10.1007/978-1-4939-2438-7_1
  4. Bernheim, A., Zhu, WJ, T., JF, C., Huang, LT, P., … Hansell DM. (2020, February 20). Chest CT Findings in Coronavirus Disease-19 (COVID-19): Relationship to Duration of Infection. Retrieved from https://pubs.rsna.org/doi/10.1148/radiol.2020200463
  5. If You Are at Higher Risk. (2020, March 12). Retrieved fromhttps://www.cdc.gov/coronavirus/2019-ncov/specific-groups/high-risk-complications.html
  6. Cascella M, Rajnik M, Cuomo A, et al. Features, Evaluation and Treatment Coronavirus (COVID-19) [Updated 2020 Mar 8]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2020 Jan-. Available from:https://www.ncbi.nlm.nih.gov/books/NBK554776/ 
  7. Dong Y, Mo X, Hu Y, et al. Epidemiological characteristics of 2143 pediatric patients with 2019 coronavirus disease in China. Pediatrics. 2020; doi: 10.1542/peds.2020-0702
  8. Clinical management of severe acute respiratory infection (SARI) when COVID-19 disease is suspected. WHO. (2020).
  9. Lauer, S. A., Grantz, K. H., Bi, Q., Jones, F. K., Zheng, Q., Meredith, H. R., … Lessler, J. (2020). The Incubation Period of Coronavirus Disease 2019 (COVID-19) From Publicly Reported Confirmed Cases: Estimation and Application. Annals of Internal Medicine. doi: 10.7326/m20-0504
  10. Zhou, F., Yu, T., Du, R., Fan, G., Liu, Y., Liu, Z., … Cao, B. (2020). Clinical course and risk factors for mortality of adult inpatients with COVID-19 in Wuhan, China: a retrospective cohort study. The Lancet. doi: 10.1016/s0140-6736(20)30566-3
  11. Kampf, G., Todt, D., Pfaender, S., & Steinmann, E. (2020). Persistence of coronaviruses on inanimate surfaces and their inactivation with biocidal agents. Journal of Hospital Infection104(3), 246–251. doi: 10.1016/j.jhin.2020.01.022
  12. Doremalen, N. V., Bushmaker, T., Morris, D., Holbrook, M., Gamble, A., Williamson, B., … Munster, V. (2020). Aerosol and surface stability of HCoV-19 (SARS-CoV-2) compared to SARS-CoV-1. doi: 10.1101/2020.03.09.20033217
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  14. Frequently Asked Questions about Personal Protective Equipment. (2020, March 14). Retrieved from https://www.cdc.gov/coronavirus/2019-ncov/hcp/respirator-use-faq.html
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