Killer Cold Virus: Questions, Answers
Despite New Ad14 Bug's Fatal Potential, Most Get Mild Illness
Nov. 20, 2007 -- It's been deadly for 10 Americans -- but most people who catch the new strain of Ad14 "killer cold virus" get only a mild illness, the CDC says.
Here's the main thing the federal health agency wants you to know: The new strain of Ad14 certainly can cause very serious disease. But it's not nearly as deadly as other bugs that circulate every winter.
Nobody knows how many more people will die from Ad14 this year -- if any. But the number is sure to be vastly smaller than the average year's toll of 36,000 deaths from flu and 11,000 deaths from respiratory syncytial virus (RSV).
What do we need to know about the new virus this winter? WebMD spoke with the CDC's Larry J. Anderson, MD, chief of the division of viral and rickettsial diseases, National Center for Infectious Diseases.
What are the symptoms of infection with the new Ad14 virus?
Anderson: "First, people should know that this is one of the adenoviruses, which can cause a wide range of things. Probably the most common is respiratory illness. This means there is a kind of layering of symptoms. First there are the symptoms of a common cold, but possibly with a fever: runny nose, sore throat, and cough. Then there may be the more severe symptoms of lower respiratory involvement: productive cough, shortness of breath.
"Almost all the 51 types of adenovirus can cause the full range of symptoms -- and so can rhinovirus, a different cold virus. What is unusual about Ad14 is the severity of symptoms. It is not that the other adenoviruses can't do this, they just don't do it this often."
Does everyone who catches Ad14 get a serious illness?
Anderson: "In the outbreak at Lackland Air Force Base, the vast majority of individuals infected with Ad14 had the more mild end of the spectrum of illness. They tended to have fever with cold, but only the minority of individuals were hospitalized. In our preliminary analysis of data from an investigation looking at recruits over the course of the six and a half weeks of military training, a little over 150 or 160 people -- about half -- got infected with Ad14. Maybe 5% had no symptoms, but nobody was hospitalized in that group.
"That is reassuring. And if you think about the epidemic in Oregon, we saw that the cases were not linked to one another. That means the virus had to have spread out in a variety of places. A lot of other people must have been infected for it to spread that broadly. This means that many people were infected that weren't all that ill."
With Ad14 possibly circulating this winter, is there anything people should do when they come down with a cold or flu-like illness?
Anderson: "Do what you usually do. Ad14 really should not change the way you look at respiratory illness this season at all. If you think about relative risk, flu regularly causes more than 30,000 deaths. RSV is a much greater risk in the young child. And rhinoviruses are likely to cause a lot more disease than Ad14. That's because this is an uncommon infection, and the more common infections will be much more of a problem.
"Now here's what you can do. Get your flu vaccination. Get your pneumococcal vaccination. And observe good hygiene -- this means frequent hand washing, and covering your mouth whenever you cough or sneeze."