WHO stresses antiviral use in high-risk H1N1 patients

Nov 12, 2009 (CIDRAP News) – Citing reports that hospitals and clinics in some countries are being overwhelmed by pandemic influenza cases, the World Health Organization (WHO) today put an exclamation on its advice about the importance of prompt antiviral treatment for high-risk patients.

Dr. Nikki Shindo said growing clinical experience has given the WHO more confidence about the safety and effectiveness of antiviral drugs, primarily oseltamivir, in patients at risk for severe disease, especially pregnant women, small children, and people with chronic medical conditions.

"In some countries hospitals and clinics are overwhelmed with the number of patients they are treating," Shindo said. "One way to lighten the burden on the healthcare system is to prevent severe disease."

Shindo spoke at a news teleconference today that followed the WHO's release of updated clinical management guidelines this week. Like the current advice from the US Centers for Disease Control and Prevention, the guidelines urge doctors not to wait for flu test results before treating at-risk patients with antivirals.

Shindo said the WHO has received reports of overwhelming numbers of pandemic flu cases in Ukraine, Afghanistan, and Mongolia in particular. The agency is sending antiviral supplies to several poor countries but doesn't have enough to meet their needs, she reported.

The agency recently shipped antivirals to Afghanistan, Mongolia, Belarus, and Ukraine and will soon be sending some to Azerbaijan and Kyrgyzstan, she reported. "We'll use the stockpile to support countries which are likely to be hard hit this winter and unable to meet their needs," she said.

With the addition of about 5 million treatment courses expected soon, the WHO will have up to 10 million courses in its stockpile, Shindo said, adding, "We don't think this is enough to meet the needs of the countries. So we've been working with our partners and other countries who have enough supplies to meet the global need."

She didn't give an estimate of how big a supply will be needed, but said, "We calculate the at-risk groups in developing countries at more or less about 4% of the population."

The WHO is recommending that countries "decentralize the distribution of antivirals and ensure that general practitioners have access to these medications for their patients," Shindo said. "Patients should not have to visit a hospital in order to get antivirals prescribed. This should ensure that individuals get the care they need faster and the burden on hospitals will be reduced."

Three recommendations
Shindo highlighted three WHO recommendations about treatment in H1N1 cases:

  • People in high-risk groups, especially pregnant women, children less than 2 years old, and those with chronic medical conditions, should receive antiviral treatment as soon as possible if they have flu symptoms.
  • People who are not in those groups but have persistent or rapidly worsening symptoms also should get antiviral medication. Particular danger signs include difficult breathing and high fever lasting longer than 3 days.
  • Those who already have pneumonia should be given both antiviral and antibiotic treatment.

"We have heard that doctors in caring for very sick patients in intensive care units report that patients arrived too late and even sophisticated medical procedures couldn't save their lives," Shindo said. "We asked doctors what could've been done differently; all of them answered that things may have been different if they'd been treated with antiviral medication early."

The WHO does not recommend antivirals for otherwise healthy people with mild illness or as preventive measure for healthy people, she noted.

She said the main reason for updating the clinical guidelines now is that experts are more confident about the safety and effectiveness of antiviral treatment than they were earlier in the pandemic. Increased experience with use of the drugs in young children and pregnant women has been particularly helpful.

In response to questions about risk factors, Shindo said children under age 2 have the highest hospitalization rate, with pregnant women second and those with chronic medical conditions, especially chronic lung disease, third.

The median age for hospitalized patients is between 20 and 35, but the median age for the most severe cases is about 10 years older, in the range of 35 to 40, she added.

She also commented that the proportion of severe cases in Ukraine is somewhat lower than what the Southern Hemisphere experienced in its recent winter flu season. "It seems a lot of patients are being admitted with rather milder symptoms than those requiring ICU care," she said.

Clinical guidelines
The new WHO guidelines say that on average, about half of hospitalized H1N1 patients have at least one underlying medical condition, but about a third of patients who end up in ICUs were healthy before they got the virus.

The document says that risk factors for severe disease in previously healthy people remain unclear. It warns that patients can deteriorate quickly, with warning signs such as shortness of breath, altered mental status, persistent high fever, and severe dehydration.

The WHO lists oseltamivir as the first choice for antiviral treatment in all patient groups, including breastfeeding mothers, with zanamivir as the backup if oseltamivir is unavailable or there are signs of resistance to it. Although starting treatment within 48 hours of illness onset is best, an antiviral "may be used at any stage of active disease when ongoing viral replication is anticipated or documented."

For hospital patients, the guidelines stress the importance of monitoring oxygen saturation by pulse oximetry and providing supplemental oxygen when needed. The WHO advises against the use of high-dose cortiocosteroids except in clinical trials.

See also:

Summary of WHO H1N1 clinical management guidelines

Full text of guidelines

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