Adequate Vaccine Coverage Trumps Oseltamivir Prophylaxis In Outbreaks.(Brief Article)

2001 APR 18 - (NewsRx.com & NewsRx.net) --

by N.R. Saltmarsh, staff medical writer - The antiviral medication oseltamivir may be useful for controlling outbreaks of influenza B, but vaccination of patients and staff in long-term care facilities remains the best way to address influenza and influenza-like illness (ILI).

Until further studies are conducted to determine its cost-effectiveness and to standardize protocols, oseltamivir's widespread use for influenza B cannot yet be justified, say researchers working in British Columbia.

R. Parker and colleagues described an outbreak of ILI and influenza B in a long-term care facility in which oseltamivir prophylaxis kept the attack rate at 10%, which compared favorably to a 19% attack rate at another local facility that did not use the antiviral under comparable circumstances.

Although the drug was successful against this outbreak and in other reports of influenza A outbreaks, it is not yet licensed for this purpose in Canada and Parker et al. were reluctant to support its widespread use.

They implicated hospital infection control measures and low vaccine coverage among staff as two other culprits that likely contributed to this outbreak. "The spread of this outbreak from the geographically separate ward to other areas of the facility in which residents had not received prophylaxis, underscores the likely role of staff as a vehicle for transmission during facility outbreaks," said Parker and associates. "While accurate staff ILI rates could not be determined, their immunization rates were low, and many staff were ill during the outbreak."

Compared to amantadine, an antiviral used against influenza A, oseltamivir has a relatively high cost and this may limit its wider acceptance, the researchers said. They emphasized, however, that cost-effectiveness would not necessarily be the first consideration in controlling outbreaks among elderly nursing home residents, who are vulnerable to serious complications from influenza ("Experience with oseltamivir in the control of a nursing home influenza B outbreak," Canada Communicable Disease Report, March ...