Smokers at Higher Risk for Swine Flu

Swine flu can be very dangerous especially for smokers, according to patient data from Hong Kong, where tobacco use was noted in almost half of severe cases.
Scientists found that twelve of 27 swine flu patients who developed pneumonia and other serious illnesses were either current or former smokers and some had no other known risk factors.
Thomas Tsang, acting controller of Hong Kong’s Centre for Health Protection, told: "The size of smokers among the serious cases is pretty high. So far this is just one remark that stands out and we need to examine it."
These findings may discard more light on an enigma that doctors are fighting with: why the swine flu remains mild for a majority of people and is severe enough to kill in others.
Scientists reported that about 1,800 people infected with H1N1 have died since the virus was discovered in April.
In Hong Kong, about 1 in 200 people tested swine flu. And about 13 percent of adults in the city smoke, Tsang added.
As drug makers race to make vaccines to fight the pandemic, health officials are trying to identify exposed groups in order to prioritize who should get vaccinated first.
Tsang explained that in Hong Kong, three-quarters of H1N1 patients with serious disease had medical factors that made them more susceptible. Chronic lung conditions such as asthma and emphysema, as well as diabetes, cardiovascular disease, unhealthy obesity and pregnancy, can put people at risk. And he is assured that cigarette smoking might be linked with one or more of these factors.
"Smokers tend to have weaker lung function and smoking is also associated with some other chronic diseases. It could be those factors that explain the association rather than smoking per se," argued Tsang.
World Health Organization continues to sustain that smoking is the biggest preventable cause of death and claims 4.9 million lives a year globally. This bad behavior is also the leading cause of sickness and earlier deaths in Hong Kong.
Nicotine, the addiction-causing chemical in tobacco, interferes with the immune response to seasonal flu, said John Mackenzie, a Melbourne-based virologist who studied the interaction in mouse models more than 30 years ago.
Mackenzie explained: "Smoking is interesting. It initially enhances the immune system, but then it depresses it. If you smoke, you become much more susceptible to straight viral pneumonia."
By hindering the body’s protection mechanisms, smoking may enable the virus to repeat undiscovered for longer and attack more of the respiratory tract, said Frederick Hayden, professor of clinical virology at the University Of Virginia School Of Medicine in Charlottesville.

Scientists concluded that the only way to reduce the risk from influenza, smokers should give up. As well they certainly should not smoke near anyone else who is ill with swine flu or at risk.