[Infectious Diseases News Brief]

National Advisory Committee on Immunization (NACI): Supplememtary Statement on Influenza Vaccine
NACI has published a supplementary statement for the 2001-2002 season on influenza vaccination of persons who experienced oculo-respiratory syndrome following previous influenza vaccination. During the 2000-2001 influenza immunization season, Health Canada received a total of 2,450 influenza vaccine-associated adverse events of which 1,735 (71%) reported ocular or respiratory symptoms. Of these reports, 39% were classified as meeting the case definition for a newly recognized "oculo-respiratory syndrome (ORS)". Of these cases, 74% were female and 71% were 30-59 years of age. The syndrome was generally mild and self-limited, about 25% of people reported oculo-respiratory symptoms lasting > 48 hours. There were no deaths reported in association with ORS. Nine hundred and twenty-five (96%) cases of ORS occurred following receipt of Fluviral_® S/F produced by BioChem Pharma (now Shire Biologics, a division of Shire BioChem Inc.), and 12 (1%) cases occurred following receipt of Fluzone_® or Vaxigrip_®, both produced by Aventis Pasteur Limited. The pathophysiologic mechanism that underlies ORS remains unknown. All three vaccines licensed in Canada during the 2000-2001 season used the same influenza strains and seed stocks; however, Fluviral_® S/F used a different splitting agent. Electron microscopic studies revealed a higher proportion of unsplit (whole) virus, and a higher proportion of aggregate virus particles in Fluviral_® S/F as compared to the other two vaccines and as compared to previous years. It has been hypothesized that the agent may not have caused adequate viral splitting, and the unsplit or aggregated (or both) virus in Fluviral_® S/F may have been etiologically associated with ORS; however, there is no conclusive evidence at this time to prove or disprove this hypothesis. To ensure the safety of the new Fluviral_® S/F vaccine, Health Canada required special studies prior to licensure. Results of these studies were made available for review by NACI, with permission of the manufacturer.
Source: Canada Communicable Disease Report, Vol 27, ACS-7, 27 November 2001

West Nile Virus: Cayman Islands, Caribbean
On 21 August 2001 a 32-year-old man from Cayman Brac, one of the Cayman Islands, was admitted into hospital with encephalitis. A serum sample taken on 29 August 2001 was found to have a very high IgM antibody reaction and a high neutralizing antibody titre to West Nile Virus. While not confirmatory, these test results, together with the clinical history of the patient, are consistent with an acute infection of West Nile Virus. The patient has been treated and is recuperating at home. The patient reported that he had not traveled out of the Cayman Islands in the last 6 months, hence this is the first suspected case of West Nile Virus in the Cayman Islands and also in the wider Caribbean Region.
Source: Fax Alert, Caribbean Epidemiology Centre, Trinidad & Tobago, 17 October 2001

Hepatitis A Virus (HAV) Infection: United Kingdom
There have been seven confirmed cases of HAV infection among injection drug users (IDUs) and one confirmed case in a close contact of that community. All the cases have been in Ipswich, and there are more suspected cases in the same risk group. The first two cases occurred in July, but subsequently there have been clusters of two to three cases every 4-5 weeks. There is evidence of a link among some of the cases. An outbreak control group has been established at the local health authority. An active information campaign has been set up, targeting drug users with advice about the signs and symptoms of HAV infection and how to prevent spread through good hygiene and vaccination. The community drug team and general practitioners have started to vaccinate IDUs. Outbreaks of hepatitis A can occur among IDUs, probably spread by direct contact and not by the bloodborne route.
Source: Communicable Disease Report Weekly, Vol 11, No 44, 1 November 2001

The details given are for information only and may be very provisional. Where incidents are considered of national importance and are ongoing, the initial report will be updated as new information becomes available.

[Infectious Diseases News Brief]