http://www.ecdc.europa.eu/en/files/...enza_Antivirals_during_Influenza_Pandemic.pdf
ECDC INTERIM GUIDANCE
Public health use of influenza antivirals during influenza pandemics
Stockholm, June 2009 [
release July 1, 2009]
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This evidence indicates that certain antiviral drugs, particularly the neuraminidase inhibitors (oseltamivir and zanamivir), offer some treatment benefits by reducing the duration of illness from influenza usually by 1?2 days
and also reducing complications and the need for antibiotics in infected individuals. This effect is limited by the need for the drugs to be given early (within 48 hours of the start of symptoms). There is also some weak evidence from observational studies that the drugs might reduce morbidity and even mortality in sicker patients even if given later than the 48 hours.
Trials in healthy adults suggest infection can be prevented with prophylaxis treatment with a 70% to 90% effectiveness rate provided the drug is taken as prescribed.
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Currently the antiviral stockpiles in European countries seem to vary from coverage of a few per cent of the population to more than 50% of the population. However, even with stockpiles in place it is almost inevitable
that demand for antiviral drugs will outweigh supply in a pandemic. Because of this, it is important that advanced strategic and logistical planning is carried out to optimise the usefulness of existing stockpiles. An important
general principle is that having stockpiles is of limited use without the agreed objectives, protocols, administration and delivery systems to go with them.
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Based on the available evidence ECDC suggests the following prioritisation strategy for antiviral use:
1 People with more severe disease. The first priority is to treat people with more severe influenza illness even if they are beyond the 48 hour ?window? following the start of symptoms when it is considered that antivirals are effective. However, for these patients it is even more important that there are adequate supplies of appropriate antibiotics available to treat secondary infections, and other essential drugs.
2 People most at risk of severe disease. Among these, priority could be given to those most at risk of developing severe disease. For seasonal influenza these are those for whom seasonal influenza vaccination is recommended: older people, those with pre-existing chronic conditions, and healthcare workers with direct patient contact. However, this may need to be modified during a pandemic to reflect those most at risk from the pandemic strain*. When both pandemic and seasonal viruses are circulating the seasonal and
pandemic higher-risk groups will need to be combined.
Some countries may want to consider giving prophylaxis in households containing people at higher risk though this would be a complicated policy to implement.
3
All people just starting an illness. After the more severe cases antivirals could be prioritised for people just starting their illness (within 48 hours of the first symptoms) because that is when these drugs are most effective.
4
Use for prophylaxis. Countries with larger stocks of antivirals can consider giving them also for prophylaxis. Candidate groups are: close contacts of cases, family contacts, and key workers for business continuity purposes. Home stockpiles are not recommended as supplies are limited though inevitably some people can be expected to request these from their doctors as they did with bird flu.
5 Healthcare workers with direct patient contact are a special case. They need to have reasonable protection with personal protective equipment.
Should they become sick they need to receive antivirals promptly and to stay home from work. Countries with larger stocks may consider prophylaxis for certain groups of these workers.
Even greater challenges are posed by the organisational aspects of antiviral delivery.
Namely the evidence indicating that antiviral treatment may only deliver its limited benefits if it is given within the first 48 hours following the start of symptoms. This will be particularly critical during a pandemic. Hence, for antivirals to be effective in treating infection, resources should also be put in place to develop protocols and systems to ensure their rapid delivery and administration.
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