Shira Kramer, MHS, PhD

What are Coronaviruses?

Coronaviruses are a family of RNA viruses that may include mild respiratory infections like the common cold, but also more severe (and potentially deadly) infections. Many are zoonotic diseases, meaning they are transmitted between animals and people. The novel coronavirus responsible for the current outbreak was identified in Wuhan, China in December 2019, and causes an illness known as COVID-19. This coronavirus is known as SARS-CoV-2.

Coronaviruses are named after the Latin word corona, meaning “crown” or “halo,” because they have “crown-like spikes on their surface,” according to the U.S. Centers for Disease Control.

What are the Symptoms of COVID-19?

Common signs of infection include runny nose, cough, fever, sore throat and shortness of breath. In more severe cases, infection can cause pneumonia, severe acute respiratory syndrome, kidney failure and even death.  Some infected individuals may show no or few symptoms at all, yet still be infectious to others.  The lack of available testing presents a major challenge in identifying affected individuals and slowing the transmission of this virus.

The severity of symptoms and poor outcomes are more common in older age groups (over age 60) and those with underlying medical conditions, such as lung disease, heart disease, diabetes, any condition causing a compromised immune system, and a chronic disease of any kind. Individuals in the highest risk groups, and those most severely affected, can experience difficulty breathing, pneumonia, failure of respiratory and other vital systems, and even septic shock.

How is the Coronavirus Transmitted?

Coronaviruses are typically transmitted from person to person through respiratory droplets and close contact. Exposure may also occur by touching surfaces that have been contaminated with the coronavirus. COVID-19 is highly infectious, and individuals may become infected through contact with both clinically ill contacts, as well as contact with individuals who have no symptoms. The highly infectious nature of this virus, the high case fatality rate, the lack of available testing, and the ability of asymptomatic persons to spread the virus are all reasons why municipalities, states, the federal government, and businesses have all restricted large gatherings, are recommending isolation to the degree possible.

What is the Incubation Period for COVID-19?

The estimated incubation period for COVID-19  is 5.1 days, with a mean of 5.5 days. A recent analysis showed that among 97.5% of infected persons, symptoms appeared 11.5 days after infection.

What is the Best Way to Control Transmission of the Coronavirus?

The World Health Organization and the U.S. Centers for Disease Control have identified several ways to slow transmission of the Coronavirus. There is no cure, and no vaccine for COVID-19. Every effort must be made to slow and control the transmission of this coronavirus.  Another important reason to slow transmission is the lack of sufficient health care resources to deal with a large surge of serious cases, which will increase the case fatality rate.  Practicing the following measures on a population scale will hopefully reduce the number of severely-affected persons and spread out the number of individuals who need hospitalization and medical care (flatten the epidemic curve).

  1. Social Isolation
    The most effective way to slow transmission of the virus is to limit social interaction, i.e., quarantine. The current recommendations in the U.S. are to limit gatherings of >10 – 50 persons, and to maintain a distance of at least 6 feet from other individuals. This recommendation has led to the cancellation of schools, shops, entertainment, meetings, travel, and normal activities for most individuals. The length of quarantine has not been established, as we still do not know the extent and progression of infection in the U.S.  However, among those with confirmed contact with an infected person(s), a two-week quarantine period is justified based upon the likely development of symptoms within 11.5 days.
  2. Meticulous and Frequent Hand Hygiene
    It is critical to wash hands frequently, for at least 20 seconds, with soap (antimicrobial or otherwise).  Hand washing should especially occur after touching surfaces or other people, after going to the bathroom, and always before eating.  Avoid touching your face, including eyes, nose, and mouth.
  3. Frequent and Thorough Cleaning and Disinfection of Environmental Surfaces and Equipment
    Since the Coronavirus can survive for days on environmental surfaces and equipment, it is highly recommended that environmental surfaces in all types of facilities be frequently and thoroughly cleaned and disinfected with an EPA-approved disinfectant. Refer to EPA List N for a comprehensive list of disinfectants approved for use against SARS-CoV-2. This list identifies all products that meet EPA’s Emerging Viral Pathogen criteria for SARS-CoV-2 and includes Sterilex Ultra Disinfectant Cleaner Solution 1 and Sterilex Ultra Step.While there is no evidence that the virus represents a food safety or animal welfare threat, food manufacturers and animal producers are taking necessary steps to protect their facilities and employee health. Building a contingency plan and implementing a robust disinfection program can help keep facilities free from COVID-19 and ensure operational continuity.Please refer to the CDC website at for additional information on the outbreak.


What are the Risks of Infection with COVID-19?

Current projections of infection and case fatality rates in the U.S., without a cure or vaccine, range from 40% – 70% of Americans infected, with 1.5 million – 1.7 million deaths.

As of March 19, 2020, the Johns Hopkins mapping system reported 222,642 worldwide confirmed cases and 9,115 deaths.  In the U.S., 9,415 COVID-19 cases and 147 deaths were reported across all 50 U.S. states.

It is challenging to calculate a precise case fatality rate (number of deaths from COVID-19 divided by the number of infected persons) because of the lack of testing and the large number of asymptomatic carriers. We know, however, that COVID-19 is at least 10 times more lethal than the common flu.

The overall case fatality rate has been estimated by the World Health Organization at 3.4%.  The lethality of the virus is not the same across age groups. According to data from the outbreaks in Italy and China, mortality rates rise significantly among older patients. In a study that has not yet been peer-reviewed, researchers at the University of Bern in Switzerland used data from the Chinese Center for Disease Control to determine that mortality rates among those infected in January and February in Hubei province shot up with each decade:

Age Group — Mortality Rate

0-9 — <.01 percent
10-19 — .02 percent
20-29 — .09 percent
30-39 — .18 percent
40-49 — .40 percent
50-59 — 1.3 percent
60-69 — 4.6 percent
70-79 — 9.8 percent
80 & up — 18 percent

It is important to note that younger persons, especially those with underlying medical conditions, are also at risk.

Further Risks Due to Limitation of Resources

The high mortality rate is made even more concerning by America’s low surge capacity — a hospital or medical system’s ability to triage and care for a major increase in patients in a short amount of time. As pediatrician Aaron E. Carroll notes in the New York Times: “It’s estimated that we have about 45,000 intensive care unit beds in the United States. In a moderate outbreak, about 200,000 Americans would need one.” In addition, with an outbreak of upper respiratory infections, another critical factor is the limited number of ventilators available in hospitals.