Are the elderly at a greater risk for coronavirus complications?

People wearing protective facemasks queue to order food from a stall in Shanghai on February 14, 2020. - Youan Hospital is one of twenty hospitals in Beijing treating coronavirus patients. Six health workers have died from the COVID-19 coronavirus in China and more than 1,700 have been infected, health officials said on February 14, underscoring the risks doctors and nurses have taken due to shortages of protective gear. less People wearing protective facemasks queue to order food from a stall in Shanghai on February 14, 2020. - Youan Hospital is one of twenty hospitals in Beijing treating coronavirus patients. Six health workers ... more Photo: Noel Celis / AFP Via Getty Images Photo: Noel Celis / AFP Via Getty Images Image 1 of / 74 Caption Close Are the elderly at a greater risk for coronavirus complications? 1 / 74 Back to Gallery

Experts agree the available data on new coronavirus cases around the world suggests elderly people who contract the virus are at a greater risk for complications and death than other individuals.

Dr. Lee Riley, a UC Berkeley professor and chair of the Division of Infectious Disease and Vaccinology, said people between the ages of 60 and 80 are at particular risk for several reasons.

"Immune system to fight infections wanes with increasing age," Riley said. "Also, underlying medial problems, for example diabetes and COPD [chronic obstructive pulmonary disease], are more common in this age group, which predispose them to respiratory infections."

Riley added that while seniors are at a higher risk, children seem to be at a lower one. It's unclear why at this point.

Dr. Charles Chiu, a professor of laboratory medicine and infectious disease at UC San Francisco, agrees: "The elderly appear to be at very high risk of severe disease from the coronavirus."

Chiu points to a study published last week looking at 44,000 confirmed cases in China, published in the Chinese Journal of Epidemiology.

"The case fatality rates increased sharply with age from 0.2% to those under 40 to 14.8% to those above 80," he said.

The study, which was not peer-reviewed by U.S. scientists, also revealed that the mortality rate in this sampling was 2.3%. It also showed men (2.8%) were slightly more likely to die than woman (1.7%).

Scientists are continuing to try to pin down the death rate as the disease spreads and evolves. The World Health Organization said Monday the rate in Wuhan, China, considered the origin of the outbreak, falls somewhere between 2% and 4%. Outside of Wuhan, it may be closer to 0.7%.

The U.S. Centers for Disease Control and Prevention said the risk for contracting COVID-19 in the United States is low. Of the 60 cases in the country, all patients except one had traveled from abroad or had been in close contact with those who traveled. On Wednesday the CDC announced the first patient, a resident of Solano County, with an infection of unknown origin has been identified.

"At this time, the patient’s exposure is unknown,'' the CDC said in a statement. "It’s possible this could be an instance of community spread of COVID-19, which would be the first time this has happened in the United States. Community spread means spread of an illness for which the source of infection is unknown. It’s also possible, however, that the patient may have been exposed to a returned traveler who was infected.''

The new virus is a member of the coronavirus family that can cause colds or more serious illnesses such as SARS and MERS. The most common symptoms are fever, coughing, wheezing and pneumonia.

Similar to the transmission of the flu, COVID-19 spreads through droplets expelled when someone coughs or sneezes, or by direct person-to-person contacts, such as by hand and or kissing. It remains unclear how long it can survive in inanimate objects and whether it can be transmitted by touching things like handles touched by an infected person.

"Currently, it’s unclear how easily or sustainably this virus is spreading between people," according to the CDC.

The best way to prevent spread of any virus is by washing your hands, covering your cough and staying home when sick, health officials said.

Amy Graff is a digital editor with SFGATE. Email her: agraff@sfgate.com.

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