Common respiratory virus more deadly than seasonal flu

Chinese University study finds the respiratory syncytial virus can be fatal for many groups and kills more people than seasonal influenza

PUBLISHED : Friday, 25 October, 2013, 3:26am
UPDATED : Friday, 25 October, 2013, 10:43am

A common respiratory virus could cause more life-threatening infections than the influenza virus, a Chinese University research team warned.

Their latest study, which is by far the largest clinical study on the respiratory syncytial virus (RSV) in Asia, found the mortality rate of those contracting RSV to be more than 11.9 per cent.

That was much higher than the 8.8 per cent mortality rate for flu patients.

"The result showed we should not underestimate these two viral infections commonly found in Hong Kong, particularly RSV," said professor Nelson Lee Lai-shun, head of the university's infectious diseases division.

"It is known that RSV causes mild upper respiratory tract infections among young children, but the study confirmed that it could cause serious and fatal infections in adults, especially the elderly and people with underlying illnesses.

"Infection among people with asthma may be particularly problematic as there is already inflammation in their respiratory tract," Lee said.

RSV usually causes mild, flu-like symptoms in most adults and children.

The symptoms include fever, sore throat and coughing, but it can cause more serious reactions in people who are aged over 60 or those with underlying illnesses, Lee said.

He added that public hospitals in the city lacked data on RSV because the disease was difficult to diagnose and there was no effective cure.

The study, published in the journal Clinical Infectious Diseases this month, analysed and compared 607 RSV and 547 seasonal influenza patients, from 2009 to 2011. It showed that 80.4 per cent of RSV patients developed complications, compared with 72.8 per cent for flu patients.

Some 42.3 per cent of patients with RSV suffered from pneumonia, while 36.7 per cent of flu patients did.

Pneumonia was the cause of more than 35 per cent of the deaths from RSV infection; others died of pneumonia combined with multi-organ failure.

The fatality rate for those who suffered RSV for 60 days stood at 11.9 per cent, compared with 8.8 per cent for the influenza virus, the study found.

Lee said RSV caused more severe illness because it attacked the upper respiratory tract.

That meant that the virus was more likely to lead to pneumonia than seasonal influenza, which attacked both the upper and lower respiratory tracts.

"I hope the study can provide a base for further research on vaccines and antiviral treatment against RSV," he said.

"The best way to avoid catching the virus is to keep good personal hygiene and take droplet precautions [from coughing and sneezing]."

The study confirmed that neuraminidase inhibitors - or antiviral drugs - were effective in fighting the influenza virus and improved survival rates of patients being treated in hospital.

But it also found that the conventional five-day treatment was inadequate, as 50 per cent of seriously ill patients continued to test positive for the virus after that period. The team recommended more prolonged treatment for flu patients.