We asked our scientists some of your most burning questions. Click below to reveal answers. Have more questions? You can send question to our scientists on our Ask A Scientist page.
What are the prospects of medical countermeasures, like vaccines or antivirals, against the COVID-19 virus?
Many groups are working on devising medical countermeasures to COVID-19. A phase I trial of a vaccine candidate has been started in Seattle, but it could take more than a year for a safe and effective vaccine to be ready to be distributed to the public.
Efforts are also underway to develop antiviral treatments, like cocktails of antibodies, that could help patients infected by COVID-19 virus. The antiviral drug remdesivir is already being tested in patients in Wuhan and early clinical trials in the U.S. are underway.
For more info, please see our answer on anti-virals.
What should I do to be prepared in case an outbreak occurs near me?
Just like people should prepare for hurricanes, people need to be prepared in case of a pandemic. DHS recommends that people have two weeks of food, water, and necessary prescription medicines; a supply of nonprescription medicines for pain, stomach issues, cold, flu, etc.; copies of electronic health records from doctors, hospitals, and/or pharmacies; and a plan for how to take care of loved ones if they get sick. These supplies will help people safely get through any decrease in normal public services or interruption in regular business. During any outbreak, individuals should also practice good hygiene to prevent the spread of illness through frequent hand washing, avoiding close contact with others, and refraining from touching one’s face.
Should I wear a mask to prevent the spread of COVID-19?
Yes. Up to 25 percent of people infected with the novel coronavirus may not exhibit symptoms, and could be able to spread COVID-19 to others by breathing or talking. Furthermore, those who are infected and who are coughing or sneezing can spread COVID-19 readily. Because of this, the Centers for Disease Control and Prevention have recommended that, in addition to staying as far away from one another as possible, we should all wear masks, regardless of how healthy we may be feeling, especially in enclosed spaces like grocery stores or pharmacies. This will help prevent us from unknowingly spreading the disease to others, and provide a limited degree of protection from contracting the virus from others.
There is currently a shortage of manufactured masks like N95 respirator and surgical masks, and these should go to healthcare providers, who are at highest risk of becoming infected, first.
It is very important to learn how to safely put on, wear, and take off masks. To learn how to make your own mask, use it safely, and clean it well, please visit this resource.
Can I use ______ to fight COVID-19?
Can I use UV light to disinfect my possessions?
UV light has been suggested as a way to disinfect objects and surfaces to mitigate the spread of the COVID-19 virus. Hospitals and laboratories often use UV light to sterilize tools and other equipment. However, that type of UV light causes human cells to multiply incorrectly as well as devastating cancers. Because of this risk, it is not recommended to use UV light to disinfect objects at home.
Researchers are experimenting with different types of UV light to develop devices that are safe for general use. The UV spectrum is broad, spanning wavelengths between 10 and 400 nanometers. The 254 nanometer UV light used by hospitals and labs to kill germs is also powerful enough to kill human cells and damage their DNA. Recent work has demonstrated the promise of far-UVC light, in the range of 207-222 nanometers, for killing germs while at the same time not harming people, but those technologies require Food and Drug Administration and Environmental Protection Agency review.
If soap or disinfectants can deactivate the COVID-19 virus, can I use it for…?
Surgical masks or N95-type masks that come in contact with soap and water should be discarded. This is because they are more likely to “vent” (leak air from the sides) and be less effective at filtering out particles. Soap also degrades the masks’ materials. Cloth masks, on the other hand, should be able to maintain their shape and integrity and should be washed with soap and water after each use.
Nose or throat
Taking a Q-tip or other object with antibacterial soap and swabbing the inside of your nostrils is not recommended as it may lead to soap poisoning. Antibacterial soap contains strong chemicals. Inhalation of these chemicals may lead to difficulty breathing. Contact of these chemicals with skin, including the skin inside your nose, may lead to irritation. This danger also applies to rubbing alcohol and hydrogen peroxide, which can cause vomiting, pain, internal bleeding, and burns. The Center for Disease Control and Prevention (CDC) strongly urges people to avoid touching your face (mouth, nose, and eyes), to thoroughly wash your hands with soap, and to wear face coverings/masks to help prevent the spread of COVID-19.
The World Health Organization has confirmed that external exposure to alcohol or chlorine bleach will not kill viruses that have already entered the body. On the contrary, exposure to these substances can be harmful to the eyes, mouth, and skin. These substances can be effective for disinfecting surfaces, but should be used while following appropriate recommendations from the manufacturer and public health experts. Bleach can kill COVID-19 virus on surfaces in five minutes, and isopropyl alcohol can destroy COVID-19 virus in under five minutes. However, chlorine bleach is toxic, can be lethal if ingested, and is an irritant to the skin.
Misinformation around this topic has been very dangerous; the US CDC has reported a 20% increase in calls about poisonings from disinfectants compared to last year.
People should use soaps and shampoos specifically for hand, body, and hair washing as recommended in order to cleanse their bodies of coronavirus.
What makes COVID-19 different from other coronaviruses?
Unlike the four strains of coronavirus behind about 20% of the cases of common cold, COVID-19 virus can cause severe illness, and even death. This is because while coronaviruses causing the common cold infect the nose and throat, which comprise the upper respiratory tract, COVID-19 virus infects the lungs, which is the lower respiratory tract. That can bring on pneumonia. The determining factor of where in the human body infection occurs is the structures on the outside of the virus that interact with the structures on the outside of cells that make up different human organs or tissues. Moreover, since coronaviruses that cause the common cold replicate in the upper respiratory tract, they are more likely to be spread than viruses that replicate only in the lower respiratory tract. Pathogens get in and out of the nose and throat more easily than the lungs, and the lungs’ defenses against viruses are more robust. The National Institutes of Health supports fundamental research into the mechanisms by which viruses infect people and replicate.
What would lead you to suspect that someone is infected with COVID-19?
Identifying people who may be infected with COVID-19 virus relies on recognizing the symptoms that are caused by infection and determining how an individual may have been exposed to COVID-19 virus. However, because people can be infected with the COVID-19 virus and spread the virus without knowing it or exhibiting symptoms, measures like keeping distance between one another, washing our hands frequently with soap and water, and wearing cloth face coverings are very important.
When infected with COVID-19 virus, some people may exhibit no or minor symptoms, while others may become very sick, or even die. Symptoms can include fever, cough, or shortness of breath. Fever is stimulated in response to viral infection because as part of the human immune response, increased body temperature is less favorable for viral replication, which is heat sensitive. Coughing is a reflex that is stimulated by an irritant, in the case of COVID-19 virus, viral particles attacking the lungs. COVID-19 can cause shortness of breath because it disrupts the lungs.
If an individual is experiencing fever or lower respiratory illness (characterized by cough or shortness of breath), it is important to learn whether the person had the opportunity to be exposed to COVID-19 virus, and how that exposure may have occurred. Tests that rule out other diseases and that can detect the COVID-19 virus may be warranted.
Public health experts believe the COVID-19 virus incubation period may range from 48 hours to 14 days after exposure. If a person is around 6 feet from an individual – a “close contact” – who can spread COVID-19, the person is at risk of contracting the virus. This is because coronaviruses can spread when infected people cough or sneeze, or possibly even exhaling or speaking, sending droplets containing the virus sailing into others’ mouths or noses, which can then even be inhaled into the lungs.
How are suspected COVID-19 infections confirmed?
If an individual is experiencing COVID-19 symptoms, they should communicate with their doctor, and based on the clinical course of illness, the individual’s travel history, recent contacts with others who may be infected, or local COVID-19 epidemiology, the individual may be isolated and tested. The US Centers for Disease Control and Prevention (CDC), other public health labs, university hospital labs, and companies have developed tests for the analysis of patients’ specimens. The CDC test relies on a technique called real-time reverse transcriptase (RT)-polymerase chain reaction (PCR). To conduct this test, COVID-19 virus genetic material needs to be extracted from specimens, such as those collected by nasal swabs. A virus’ genetic material is usually made out of the nucleic acids ribonucleic acid (RNA) or deoxyribonucleic acid (DNA). Because viral genetic material – in the case of COVID-19 virus, viral RNA – would be present in relatively low amounts, the amount of nucleic acid that denotes viral presence needs to be boosted in order for it to be detected. The amplification and monitoring of nucleic acid from initial COVID-19 virus RNA is performed using real-time RT-PCR, which reads out viral RNA into DNA, and then copies the DNA over and over again, generating a detectable signal if the specimen contained COVID-19 virus. In theory, a single copy of the COVID-19 virus RNA genome is detectable by real-time RT-PCR; in practice, coronaviruses need to replicate in order for there to be enough genetic material that can be used for the test.
Can people infected with COVID-19 virus spread the germ before appearing or feeling ill?
Dr. Anthony Fauci, Director of the National Institute of Allergy and Infectious Diseases (NIAID), noted that during his conversations with colleagues in China “they told me without a doubt there is some degree of asymptomatic transmission.” Furthermore, Dr. Robert Redfield, director of the Centers for Disease Control and Prevention (CDC), said “there’s been good communication with our colleagues to confirm asymptomatic infection, to confirm asymptomatic transmission, to be able to get a better handle on the clinical spectrum of illness in China.” This would indicate that the virus can indeed be spread prior to the onset of symptoms such as coughing, fever, and shortness of breath.
However, national and international health organizations working to mitigate the spread of the virus are still collecting data on asymptomatic transmission, and since people who cough or sneeze are more likely to spread it than people who exhibit no symptoms, groups like the World Health Organization (WHO) say that asymptomatic transmission plays minor roles in epidemics. The Centers for Disease Control and prevention website will update with definitive information about how COVID-19 virus spreads.
How are vaccines made?
Vaccines are critical tools for preventing the spread of disease, and are challenging to develop. A vaccine stimulates a person’s own immune system to defend against infectious viruses the person may encounter.
There are a number of approaches for developing a vaccine. Whole pathogens can be weakened, or entirely inactivated, and used to inoculate people. Or a part of a pathogen can be tested for its ability to stimulate a person’s immune system and provide protection.
Vaccine production can be egg-based or cell-based. Egg-based production relies on large numbers of chicken eggs, requires working with active virus, and can take a long time. Cell-based production uses cells cultured in the lab, is compatible with recombinant technology (which allows a lab to start the vaccine production process with genetic information about the virus, rather than a physical sample of the active virus), and has the potential to be conducted more rapidly.
After limited production and successful clinical trials, vaccine manufacturing is scaled up, and vaccines can be distributed to the general public.
Federal stakeholders: Centers for Disease Control and Prevention, National Institutes of Health, Department of Defense, Department of Homeland Security
Can we use antivirals to treat COVID-19?
Governments, pharmaceutical companies, and international health organizations are racing to determine ways to treat or prevent the spread of COVID-19. One of the ways that is being explored is the development of new, or the use of existing, antivirals. Viruses are packets of RNA or DNA inside a protein capsule that are absorbed by healthy cells and instruct them to make copies of the virus and release them. Antivirals work by interfering with important proteins in the viruses that allow them to enter cells, multiply, or escape from infected cells.
Scientists are currently testing different types of antivirals that work against influenza, HIV, and even Ebola, to see if they are effective against COVID-19 virus. In animal models, scientists have found that a drug that was developed by Gilead for Ebola called remdesivir, can prevent coronaviruses like Severe Acute Respiratory Syndrome (SARS) and Middle East Respiratory Syndrome (MERS) from replicating and infecting healthy cells. Because SARS and MERS are similar to COVID-19, scientists are looking to apply these results to models of COVID-19.
Medical experts in China are already treating patients with remdesivir to try to reduce the severity of their symptoms. An individual in the U.S. who was treated with remdesivir saw improvement in his symptoms in one day. However, it is important to note that this treatment is highly experimental and scientists need more information to determine if it is widely effective against COVID-19 before administering it to the general population.
The National Institutes of Health sponsors fundamental research that underpins the development of antivirals.
What is the survivability of the novel coronavirus outside of the human body?
Viruses are vulnerable outside our bodies because of how they are built. Specifically, they are pieces of RNA or DNA contained in a special coating of proteins called capsids. Viruses cannot replicate unless absorbed by cells in our body. Once a virus is outside the body, its capsid starts to degrade, and the more degraded its capsid is, the less likely it is to survive. When outside the body, these capsids degrade faster in cold, dry environments. They also degrade faster on soft, rather than on hard surfaces. That’s because they need moisture to survive and soft surfaces absorb that moisture. While it is difficult to determine exactly how long viruses can stay intact outside the body, since it is so dependent on environmental conditions, different viruses do appear to have different levels of resiliency. Flu viruses, for example, are generally rendered harmless after nine hours on hard surfaces and four hours on soft surfaces. The Middle East Respiratory Syndrome (MERS), which is in the same virus family as COVID-19 virus, and lasts for two days on hard surfaces, and a recent study concluded that human coronaviruses can last on surfaces at room temperature for up to 9 days.
The World Health Organization’s early estimates suggest that COVID-19 virus “may persist on surfaces for a few hours or up to several days.” Surfaces can be cleaned with household disinfectants, and be sure to wash your hands.
The Centers for Disease Control and Prevention website will update with definitive information about the survivability of COVID-19 outside the human body.
How do reports of confirmed cases compares with scientific projections?
Research modeling the early stages of the COVID-19 outbreak consistently suggested that the number of people infected by COVID-19 was likely considerably higher than the reported numbers of confirmed cases.
For example, work led by a researcher at Northeastern University estimated that as of Wednesday, January 29th, 31,200 people in Wuhan alone could have been infected, compared to the reported 2,261 confirmed cases.
Discrepancies between estimated and reported COVID-19 cases could be due to infected people with no or minor symptoms not seeking medical attention, backups of specimen testing, or other healthcare system shortages.
The US Centers for Disease Control and Prevention is tracking the outbreak and coordinating with state and local public health officials to minimize the spread of the COVID-19 virus.
Experts: Steven Hoffman, Daniel Lucey
Where can specimens from patients suspected to be infected with novel coronavirus be sent for testing in the US?
At the beginning of the COVID-19 outbreak, samples could only be tested at the Centers for Disease Control (CDC) headquarters in Atlanta, Georgia. However, as the outbreak grew, local health officials needed to be able to quickly confirm whether a patient contracted the disease, instead of waiting for CDC to perform the analysis themselves. CDC then asked the Food and Drug Administration (FDA) for an emergency approval of the necessary tests so local officials could rule out cases on their own.
The FDA had to approve the use of these tests because it is in charge of how medical countermeasures and diagnostics are used in the U.S. population. In public health emergencies, such as the COVID-19 outbreak, sometimes tests and treatments for similar diseases can be adapted for use during the emergency. To use these tests and treatments in an “off-label” way, the FDA has to issue a temporary Emergency Use Authorization (EUA). EUA have been used to help treat people during a number of recent public health emergencies, like the Ebola, Zika, and Middle East Respiratory Syndrome (MERS) outbreaks.
Now, some public health labs, university hospital labs, and medical testing companies have developed tests, and testing is being carried out throughout the US, although capacity is limited in some areas.
How accurate is the test the CDC developed to test specimens from patients suspected to be infected with novel coronavirus?
The US Centers for Disease Control and Prevention (CDC) has developed a test for the analysis of patients’ specimens. The test relies on a technique called real-time reverse transcriptase (RT)-polymerase chain reaction (PCR). To conduct this test, COVID-19 virus genetic material needs to be extracted from specimens, such as those collected by nasal swabs. A virus’ genetic material is usually made out of the nucleic acids ribonucleic acid (RNA) or deoxyribonucleic acid (DNA). Because viral genetic material – in the case of COVID-19 virus, viral RNA – would be present in relatively low amounts, the amount of nucleic acid that denotes viral presence needs to be boosted in order for it to be detected. The amplification and monitoring of nucleic acid from initial COVID-19 virus RNA is performed using real-time RT-PCR, which reads out viral RNA into DNA, and then copies the DNA over and over again, generating a detectable signal if the specimen contained COVID-19 virus. In theory, a single copy of the COVID-19 virus RNA genome is detectable by real-time RT-PCR; in practice, coronaviruses need to replicate in order for there to be enough genetic material that can be used for the test. More field testing of this assay with real patient samples is necessary to determine its true accuracy.
After the CDC submitted a request for emergency authorization to the Food and Drug Administration, FDA issued an expedited approval of the assay, and it can now be used by state health labs as well as CDC. Other organizations are working on the development of different COVID-19 diagnostics that could potentially be more rapid or more sensitive.
What do we know about the clinical severity of the COVID-19 virus?
When infected with COVID-19, some people may exhibit no or minor symptoms, while others may become very sick, or even die. The main COVID-19 symptoms include fever, cough, and shortness of breath. The severity of the virus ranges from person to person. Older people and people with preexisting health issues such as heart and lung disease have had a higher risk of developing more severe COVID-19 illnesses.
A large World Health Organization study of nearly 56,000 confirmed cases in China showed that about 80% of cases were mild to moderate, while 14% were severe and 6% were critical. Critical cases exhibited respiratory failure, septic shock, and/or multiple organ dysfunction/failure.
As of April 13, around 6.2% of reported COVID-19 cases (globally) had died. The current mortality for known cases of COVID-19 is about 2.1% in South Korea and 2.4% in Germany, countries where there has been widespread testing. By comparison, seasonal flu generally kills about 0.1% of those infected on average.
Because many mild or asymptomatic COVID-19 infections go unreported, it is thought the case fatality ratio is lower than 2%, possibly about 1%; but that would still mean that COVID-19 is at least ten times more deadly than the flu.
For the most recent counts of confirmed COVID-19 cases, deaths, and recoveries, visit this dashboard.
What protective equipment is most effective for healthcare workers?
The Occupational Safety and Health Administration (OSHA) recommends that healthcare workers use a combination of standard procedures to protect themselves, including wearing gowns, gloves, National Institute for Occupational Safety and Health (NIOSH)-certified disposable N95 or better respirators, and eye/face protection. According to the Food and Drug Administration (FDA), “the ‘N95’ designation means that when subjected to careful testing, the respirator blocks at least 95 percent of very small [300 nanometer] test particles.” The diameter of COVID-19 virus particles is reported to be about 60 to 140 nanometers. However, this mask is not suitable for children, people with facial hair, and those with respiratory conditions such as asthma.
The face masks that are most often used by the public are generally considered ineffective against the spread of disease because they often do not create a tight seal against the face and offer little protection when moist. The cloth reusable face masks offer even less protection because often people do not clean them properly and can actually transmit diseases to the wearer through the moisture trapped on the inside and outside of them. Doctors recommend that only sick individuals use face masks to temporarily prevent the spread of disease to others.
Why has the name of the coronavirus causing the current outbreak - COVID-19 - changed over the course of the epidemic?
The World Health Organization (WHO) has decided to name the disease caused by the novel coronavirus “COVID-19” and refers to the virus that causes it as the “COVID-19 virus.” CO for corona, VI for virus, D for disease, and 19 for the year the outbreak was first recognized, late in 2019. Separately, the Coronavirus Study Group of the International Committee on Taxonomy of Viruses has named the new virus severe acute respiratory syndrome-related coronavirus 2, or SARS-CoV-2; however, this name has generated controversy in the public health and infectious disease community.
Before being officially named, the virus was commonly referred to as 2019 novel coronavirus, shortened to 2019-nCoV, or, in some cases, called Wuhan coronavirus, although the stigmatizing nature of that nomenclature is not preferable.
The director of the Office of Global Affairs at the Department of Health and Human Services, Mr. Garrett Grigsby, represents
the US at the WHO.
For the most recent counts of confirmed COVID-19 cases, deaths, and recoveries, visit this dashboard.
What protective equipment is most effective for healthcare workers?