With the coronavirus epidemic spreading, the Centers for Disease Control is recommending that people avoid cruise ship travel for now. The warning is particularly aimed at older people and those with chronic health conditions such as heart disease and diabetes, as they seem to be at higher risk of experiencing severe cases of COVID-19 if they contract it.

SARS-CoV-2, the coronavirus that causes COVID-19, is thought to spread primarily from person to person, which means large gatherings of individuals in closed quarters -- which are natural features of cruises -- create ideal conditions for it to spread.

Passengers and crew aboard the Grand Princess have been stuck on that vessel for days off the coast of San Francisco. As of March 6, 21 people on the cruise ship had tested positive for COVID-19 -- 19 crew members and two guests. Authorities are to begin what they expect to be a multiday process of disembarking the more than 2,400 passengers Monday. All will face another 2 weeks of quarantine

Nurse holding test tube with blood for Coronavirus testing

Image Source: Getty Images.

The race to prevent a COVID-19 pandemic continues

There are now more than 500 confirmed cases of the potentially deadly disease in the U.S. across more than two dozen states. Several biotechnology companies are currently racing to find a treatment or a vaccine for COVID-19. This list includes Gilead Sciences (GILD -0.48%), which recently initiated two phase 3 clinical trials investigating the efficacy of its antiviral product -- remdesivir -- as a treatment for COVID-19.

One of the trials will involve 400 patients with "severe clinical manifestations" of COVID-19, and the other will enroll 600 patients with moderate manifestations of the disease.

In each trial, patients will be given daily oral doses of remdesivir for five or 10 days. Remdesivir was originally developed as a treatment for Ebola, but it showed little success against that disease.

Other companies such as Inovio Pharmaceuticals (INO -3.23%) and Novavax (NVAX 23.49%) have developed potential vaccines for COVID-19; however, neither has started clinical trials of their candidates yet.