Frequently Asked Questions About COVID-19

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1) How did COVID-19 begin?

According to the World Health Organization, on 31 December 2019, the WHO China Country Office was informed of cases of pneumonia of unknown etiology (unknown cause) in Wuhan City, Hubei Province of China.  On January 7, 2020, this virus was identified as a novel type of coronavirus.  On January 11 and 12 2020, the WHO received information that the outbreak may have been associated with exposures to a seafood market in Wuhan City, China.  This led to the initial hypothesis that the spread was animal-to-human.  However, it was later discovered that person-to-person spread was occurring.  It is now known that the mode of transmission of COVID-19 is by respiratory aerosol and is spread from person-to-person.

2) What is the incubation period for COVID-19?

The mean incubation period is 5.5 days with the great majority symptomatic by 11.5 days.  Only 1 per 10,000 will turn positive greater than 14 days after exposure.  (Ann Intern Med 2020 Mar 10; [e-pub]. (

3) What are risk factors for severe illness associated with COVID-19?

Data reported from the CDC indicates the elderly (adults >65) are at a higher risk of developing severe complications due to COVID-19.  They also report that the elderly are at higher risk of death due to these complications.  Individuals of any age with underlying comorbid conditions such as heart disease, lung disease, cancer, liver disease, kidney disease, diabetes, those with a BMI >30 and those with immunocompromised states are at higher risk to develop serious illness. Those with asthma, HIV, and those who are pregnant are also considered potential high groups. 

Regarding pregnancy, the CDC states now states that pregnant individual may be at greater risk severe illness associated with COVID-19.  Mortality rates do not differ from that associated with the general population.

Please see here for more information on COVID-19 and pregnancy.

Specifically regarding the elderly, the CDC urges this population to exercise increased caution as this age group is particularly vulnerable to COVID-19 related illness and has an increased risk of hospitalization and subsequent mortality.  The CDC reports that 8 out of 10 COVID-19 hospitalizations have occurred in individuals 65 years and older. Out of all COVID-19 cases reported in the US that required hospitalization 31-59% were adults age 65-84 and 31-70% were adults 85 years old and older. Of those that required admission to an ICU, 11-31% were 65-84 years old and 6-29% were 85 years old and older.  Of those who died 4-11% were 65-84 years old and 10-27% were 85 years old and older.  

4) What are signs and symptoms of COVID-19 in adults?

The signs and symptoms associated with COVID-19 are variable and can mimic many other illnesses.  According to the CDC, the following signs and symptoms are associated with COVID-19 at time of illness onset: fever, constant or intermittent (83-99%), cough (59%–82%), fatigue (44-70%), anorexia (48-80%), shortness of breath (31-40%), sputum production (28-33%), and myalgias (11-35%).  The CDC also noted that while fever was present in only 44% of patients at the time of hospital admission, 89% of patients became febrile during their admission.  Other possible symptoms include sore throat, headache, productive cough, nausea, and diarrhea, but these occurred in <10% of patients.

5) Are children at increased risk of developing COVD-19?

According to the CDC, otherwise healthy children do not appear to have a higher than average risk of contracting COVID-19 as compared to adults, nor do they manifest a greater severity of illness based on available data. Children have actually shown to be at a lower risk for severe illness than adults.  In the United States, <2% of all COVID cases have occurred in those <18 years of ago. According to data provided by the CDC, among children in China, illness severity was lower in COVID positive children with 94% having asymptomatic disease, mild or moderate disease, only 5% having severe disease, and <1% having critical disease. A very small percentage of children have developed multisystem inflammatory syndrome in children (MIS-C) associated with COVID-19.

Please see here for more information on COVID-19 and children.

6) What are treatments for COVID-19?

Treatments for COVID are discussed in full here.

7) What is the mortality rate of COVID-19?

Age and underlying medical conditions are key in predicting outcomes of patients with COVID-19.  The most recent data provided by the CDC was as of April 3, 2020.  The overall case fatality rate has been reported as 2.3%.  The case fatality rate for those requiring ICU admission is 49%. As per data provided by the CDC, among U.S. COVID-19 cases with a known disposition, the proportion of persons who were hospitalized was 19%.  The proportion admitted to the intensive care unit (ICU) was 6%.   The elderly are at greatest risk of dying from COVID-2019.  Early data from the US as reported by the CDC indicates the case fatality is highest in persons aged ≥85 years (10%–27%), followed by 3%–11% for ages 65–84 years, 1%–3% for ages 55–64 years, and <1% for ages 0–54 years.

8) Can patients become reinfected with COVID-19? 

The CDC reports that there is not yet enough data to fully answer this question. Data from similar viruses, such as MERS-CoV infection suggests possible short-term immunity, but there is no data to substantiate this claim.  Early claims of reinfection were thought to be due, at least in part, to false negative laboratory tests.

9) Can my pet contract COVID-19?

The CDC reports there have been a small number of cases of domestic and zoo animal infections with COVID-19 in the United States. Most cases have been human-to-animal spread. The risk of animal-to-human spread is considered to be low.  Current recommendations from the CDC indicate that individuals infected with COVID-19 on home isolation should restrict interaction with household pets, in addition to following other prevention measures just as they would to protect other household members from COVID-19. Specifically, while a person with COVID-19 is symptomatic, they should maintain separation from household animals. If possible, a household member should be designated to care for the pets. If a person with COVID-19 must care for pets or other animals, they should ensure they wash their hands before and after caring for them. In accordance with the Americans with Disabilities Act service animals should be permitted to remain with their handlers. Guidance for testing in animals can be found HERE.

10) What are the differences between a surgical mask and an N95 mask?

Please see this infographic from the CDC to understand the differences.

11) Should individuals wear a mask when going out in public to prevent contracting COVID-19?

At this time, the CDC is recommending cloth face coverings when less than 6 feet apart from other people or indoors.  This is to help slow the spread of the virus and help asymptomatic individuals from transmitting it to others. The CDC recommends that N95 masks be reserved for healthcare providers, used under the current CDC guidelines. 

12) What are restrictions for critical workers exposed to individuals with COVID-19?

New CDC guidelines were released on April 8, 2020 stating that critical infrastructure workers may be permitted to continue work following potential exposure to COVID-19, provided they remain asymptomatic and additional precautions are implemented to protect them and the community.  The full CDC statement can be viewed HERE.

13) What are the rates of asymptomatic COVID-19 infection and how does that impact transmission?

According to the CDC, the rates of asymptomatic COVID-19 infection are not fully known since routine testing does not occur in asymptomatic individuals. One study found that as many as 13% of positive children were asymptomatic.  Another study reported by the CDC reported that as many as half of COVID-19 positive skilled nursing facility residents were asymptomatic or pre-symptomatic at the time of testing.  The exact degree of virologic shedding that confers transmission of COVID-19 is not yet known.  Therefore, the risk of transmission during asymptomatic infection is also not known. The risk of infection is thought to be greatest during times when patients are symptomatic and viral loads are highest.

Julie Grishaw, ACNP

Senior Editor, McGraw-Hill Education

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