Canadian health authorities will not change their practice of prescribing the anti-viral drug Tamiflu to treat cases of pandemic H1N1 flu in children, despite a new study that raises questions about the drug’s effectiveness.
Researchers at the University of Oxford cautioned about the broad use of anti-viral drugs to treat children 12 years of age and younger suffering from seasonal flu. They found anti-viral drugs have little or no effect on asthma flare-ups, ear infections or bacterial infections in children. Tamiflu was also linked to increased vomiting.
The authors questioned whether children would face the same risks when being treated with anti-virals for the pandemic H1N1 flu virus.
But the Public Health Agency of Canada assured parents Monday that Tamiflu has a strong safety profile, and has recommended doctors prescribe it for infection prevention and to treat cases of H1N1 in infants under one year.
“We know that Tamiflu thus far is effective in treating the vast majority of people who have H1N1, making their symptoms less severe and the illness lasting fewer days,” the agency said in an e-mail. “We now have some evidence that there seems to be less risk in using Tamiflu in young children.”
The pandemic virus has shown resistance to Tamiflu, one of two anti-virals that can keep it in check if taken within days of the first symptoms. However, there have been people who have fallen ill despite taking the drug.
The study, published Monday in the British Medical Journal, found anti-virals shortened the duration of seasonal flu in children from between a half-day and 11/2 days. But the study found no clear evidence the anti-virals prevent complications in children with seasonal flu. It didn’t prevent asthma exacerbations in asthmatic children or lower rates of antibiotic prescriptions, for example.
The researchers did not study the effects of anti-virals on children with H1N1 flu, but said that based on some evidence, anti-virals might have “limited” effects on preventing complications.
“While morbidity and mortality in the current pandemic remain low, a more conservative strategy might be considered prudent, given the limited data, side effects such as vomiting, and the potential for developing resistant strains of influenza,” Matthew Thompson, a senior clinical scientist at Oxford, and his colleagues concluded.
The researchers conducted a scientific review of seven previous studies, known as a meta-analysis, on the use of anti-viral drugs for seasonal flu in children. Four studies looked at the treatment of influenza, the other three looked at the use of drugs to prevent infection.
Grant Stiver, a professor of medicine in infectious diseases at Vancouver General Hospital and the University of British Columbia, dismissed the findings. “I don’t think I would base any clinical judgment on this study,” Dr. Stiver said in an interview.
Trials done on Tamiflu have shown the drug to have benefits when it comes to seasonal flu, even in children, he said.
Although there isn’t much data on anti-virals and the H1N1 virus, Dr. Stiver said Tamiflu helps prevent the spread of infection in the early stages and, more importantly, in the absence of a vaccine.
“I think it’s safe in children,” Dr. Stiver said. “The earlier you can get this drug, the better it works.”
Although there isn't much data on anti-virals and the H1N1 virus, Dr. Stiver said Tamiflu helps prevent the spread of infection in the early stages and, more importantly, in the absence of a vaccine.
“I think it's safe in children,” Dr. Stiver said. “The earlier you can get this drug, the better it works.”
