2019 novel coronavirus (COVID-19) is a new strain of a virus causing an outbreak of respiratory illnesses. The illness was first detected in Wuhan, China, in December 2019, with cases now identified globally. For the most current statistics, please refer to the Johns Hopkins Coronavirus Resource Center for Coronavirus COVID-19 Global Cases tracking.

Overview

The COVID-19 is from a large family of human coronaviruses named for crown-like spikes on their surface with the main subgroupings classified as alpha, beta, gamma, and delta. First identified in the 1960s, there are seven coronaviruses that can infect humans.1

  • 229E (alpha coronavirus)
  • NL63 (alpha coronavirus)
  • OC43 (beta coronavirus)
  • HKU1 (beta coronavirus)
  • MERS-CoV (beta coronavirus)
  • SARS-CoV (beta coronavirus)
  • 2019 novel coronavirus

Coronavirus infections range from the common cold to the rare and deadly varieties of severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS). The MERS-CoV, SARS-CoV, and COVID-19 are examples of virus evolution that began with animals and have now become a threat to humans.

Variants

Viruses are known to change through mutation and new variants continue to emerge. There are multiple variants of the COVID-19 documented with five variants currently documented in the United States. According to the CDC, three classifications for the SARS-CoV-2 are being monitored: Variant of Interest (VOI), Variant of Concern (VOC), and Variant of High Consequence (VOHC).2 Variants circulating in the US are B.1.1.7, B.1.351, P.1, B.1.427, and B.1.429 variants and considered variants of concern. Variants of high consequence are yet to be identified in the US.

Characteristics of Variants of Concern2

Name First Detected Attributes
B.1.1.7

United Kingdom

~50% increased transmission, potential increased severity; no impact on susceptibility to a certain monoclonal antibody treatments and minimal impact on neutralization by convalescent and post-vaccination sera

B.1.351

South Africa

~50% increased transmission, significantly reduced susceptibility to a specific combination monoclonal antibody treatment, and reduced neutralization by convalescent and post-vaccination sera
B.1.427

California

~20% increased transmissibility, modest decrease in susceptibility to a specific combination monoclonal antibody treatment with the clinical implications of the decrease not fully known at this time; reduced neutralization by convalescent and post-vaccination sera

B.1.429

California

~20% increased transmissibility, reduced susceptibility to a specific combination monoclonal antibody treatment with the clinical implications of the decrease not fully known at this time; reduced neutralization by convalescent and post-vaccination sera
P.1

Japan/Brazil

Significantly reduced susceptibility to a combination monoclonal antibody treatment and reduced neutralization by convalescent and post-vaccination sera

 

Signs and symptoms

This list does not include all possible symptoms but may include:

  • Fever or chills
  • Cough
  • Shortness of breath or difficulty breathing
  • Muscle or body aches
  • Headache
  • Sore throat
  • New loss of taste or smell
  • Congestion or runny nose
  • Nausea or vomiting
  • Diarrhea

Those with severe underlying medical conditions and older adults remain at higher risk
for developing serious complications from COVID-19 infection.3

Transmission

The primary mode of SARS-CoV-2 infection is by exposure to respiratory droplets that carry the infectious virus. Contracting COVID-19 through contact with contaminated surfaces or objects is possible but the risk is generally considered to be low.4

Guidance for unvaccinated

Slowing the spread of COVID-19 infection can be accomplished by getting the COVID-19 vaccine when it is available, wearing a mask that covers your nose and mouth, staying six feet apart from others not in same household, avoiding crowds and poorly ventilated indoor spaces, and washing hands with soap and water or using hand sanitizer when soap and water are not available.5

Guidance for fully vaccinated

Fully vaccinated is considered two weeks after receipt of the second dose in a two-dose series, or two weeks post injection of a single-dose vaccine. If fully vaccinated, activities done prior to the pandemic may resume. Activities without wearing a mask or physically distancing, except where required by federal, state, local, tribal, or territorial laws, rules, and regulations, including local business and workplace guidance, may also begin.6

Diagnosis

The CDC recommends that anyone with any signs or symptoms of COVID-19 get tested, regardless of vaccination status or prior infection. Fully vaccinated people with no COVID-19 symptoms do not need to be tested following an exposure to someone with COVID-19. Those who have tested positive for COVID-19 within the past 3 months and recovered do not need to get tested following an exposure if no new symptoms occur.7

The two types of viral tests - nucleic acid amplification tests (NAATs) and antigen - test for current infection. The antibody or serology test assesses past infection. The type of viral COVID-19 tests offered may differ by location.7

Prevention

COVID-19 vaccines are now available for everyone aged 12 and older, without cost. The current vaccines are the two-dose Pfizer-BioNTech and Moderna and the one-dose Johnson and Johnson’s Janssen.8 The COVID-19 vaccines are effective at protecting you from getting COVID-19 or help keep you from getting seriously ill if you do contract COVID-19. How long the COVID-19 vaccines offer protection is still being studied.8

Treatment

The antiviral drug, Remdesivir, is the only drug with current approval by the Food and Drug Administration (FDA) for the treatment of COVID-19. Monoclonal antibodies have Emergency Use Authorization (EUA). Supportive care for symptom relief remains recommended for mild cases. A COVID-19 Treatment Guidelines Panel has given suggestions for therapeutic management of mild to moderate cases, high risk for clinical progression, and severe disease patients.9 The Panel regularly reviews clinical data in order to provide up-to-date treatment recommendations.

Guidance for health care providers

References

  1. Human coronavirus types. Centers for Disease Control and Prevention website. Last accessed May 5, 2020.
  2. SARS-CoV-2 Variant Classifications and Definitions. Centers for Disease Control and Prevention website. Accessed June 9, 2021
  3. Symptoms of COVID-19. Centers for Disease Control and Prevention website. Accessed June 8, 2021.
  4. Science brief: SARS-CoV-2 and surface (fomite) transmission for indoor community environments. Centers for Disease Control and Prevention website. Accessed June 8, 2021.
  5. Guidance for unvaccinated people: How to protect yourself & others. Centers for Disease Control and Prevention website. Accessed June 8, 2021.
  6. When you’ve been fully vaccinated: How to protect yourself and others. Centers for Disease Control and Prevention website. Accessed June 8, 2021.
  7. COVID-19 testing overview. Centers for Disease Control and Prevention website. Accessed June 8, 2021.
  8. Preparing for your COVID-19 vaccination. Centers for Disease Control and Prevention website. Accessed June 8, 2021.
  9. Coronavirus disease 2019 (COVID-19) treatment guidelines. National Institute of Health website. Accessed June 9, 2021.

Visit the COVID-19 Resources for more information.