Health behavior associated with influenza vaccination among healthcare workers in long-term-care facilities.

OBJECTIVE: To investigate the health behavior associated with influenza vaccination among healthcare workers (HCWs) in long-term-care facilities. DESIGN: A cross-sectional, self-administered survey of HCWs, augmented with focus groups to further examine attitudes toward influenza vaccination. SETTING: Two long-term-care facilities participated in the survey. The focus groups were held at one of the two facilities. PARTICIPANTS: All HCWs were invited to participate in the survey and all nonmanagerial staff members were invited to participate in the focus groups. The response rate for the survey was 58% (231 of 401). RESULTS: Vaccinated HCWs had a more positive attitude toward influenza vaccination and a greater belief that the vaccine is effective. This was not accompanied by differences in vaccine knowledge or values of potential preventive outcomes. Nonvaccinated respondents were more likely to believe that other preventive measures, such as washing hands, taking vitamins and supplements, eating a nutritious diet, exercising, and taking homeopathic or naturopathic medications, were more effective than vaccination. Additional findings from the focus groups suggest that HCWs believe that the main purpose of influenza vaccination programs is to protect residents' health at the expense, potential harm, and burden of responsibility of the staff. CONCLUSIONS: This study identifies challenges to and opportunities for improving vaccination rates among HCWs. A message that emphasizes the health benefits of vaccination to staff members, such as including vaccination as part of a staff "wellness" program, may improve the credibility of influenza immunization programs and coverage rates.

Influenza revaccination of elderly travelers: antibody response to single influenza vaccination and revaccination at 12 weeks.

The antibody response to a single influenza vaccination and the effect of influenza revaccination was assessed in healthy elderly persons. Travelers > or =65 years old who had received influenza vaccine before travel were enrolled in the study and were offered a second vaccination after 12 weeks. Geographic and age-matched control subjects received a single vaccination. A second influenza vaccination was not associated with increased adverse effects. There was no significant difference between log(10) hemagglutinin-inhibiting (HI) antibody titers or an HI antibody titer > or =1:40 (considered to be protective) in 28 control subjects and 28 revaccinated travelers for any antigen. Probable protection for influenza A antigens remained high 24 weeks after a single immunization and revaccination (A/Sydney/05/97 [H3N2], 92% and 96%, and A/Beijing/262/95 [H1N1], 80% and 96%, respectively). Response to B/Harbin was less throughout the study. A/Sydney antibody titer was lower with more times vaccinated in the previous 5 years. Therefore, a second vaccine did not enhance the immune response.

Previous creatinine levels safely predict amantadine dose for influenza A outbreak control.

BACKGROUND: Amantadine, an antiviral agent, is the only drug currently approved in Canada for prophylaxis of influenza A virus infection. To minimize side effects, the amantadine dose is adjusted for age and estimated creatinine clearance (CrCl) based on plasma creatinine (Cr) levels. As amantadine is used more frequently for influenza A outbreak control in care facilities for elderly people, physicians are increasingly called on to prescribe it for residents and to consider the necessity of requesting plasma Cr levels. OBJECTIVE: To determine whether previous Cr levels are predictive in estimating current CrCl and safe amantadine dose determination. DESIGN AND SETTING: Residents' charts were reviewed in two facilities in Vancouver, British Columbia. CrCl estimated using previous or current Cr results, current weight and age, as well as recommended amantadine doses based on Canadian National Advisory Committee on Immunization guidelines, were studied. RESULTS: 165 charts with Cr results in March 1998 were included; 122 had results before March 1998, and 103 had Cr results after March 1998. Pearson's correlation coefficient for CrCl estimated from current and previous Cr values was 0.929 for results less than six months previously, 0.974 for six to 12 months previously and 0.952 for 12 to 18 months previously. The same or a more conservative dose of amantadine was predicted in 92% of cases when using a Cr result taken within the previous year and in 76% of cases when using a Cr result taken 12 to 18 months previously. CONCLUSION: In long term care facilities, Cr levels measured up to 12 months previously can usually safely be used to estimate CrCl. Using previous Cr results permits advance preparation of doctor's orders for amantadine prophylaxis and avoids repeating Cr testing on every resident when an outbreak occurs, reducing related staff time and cost.

Cruise ships: high-risk passengers and the global spread of new influenza viruses.

In 1997, passengers on North American cruises developed acute respiratory illnesses (ARIs); influenza was suspected. We reviewed 1 ship's medical records for 3 cruises: cruise 1 (31 August to 10 September 1997), cruise 2 (11-20 September 1997), and cruise 3 (20-30 September 1997). Medically attended ARI was defined as any 2 of the following symptoms: fever (temperature, > or =37.8 degrees C) or feverishness, sore throat, cough, nasal congestion, chills, myalgia, and arthralgia. During cruise 2, we collected nasopharyngeal swabs for viral culture from people with ARI and surveyed passengers for self-reported ARI (defined as above except feverishness was substituted for fever). The outbreak probably began among Australian passengers on cruise 1 (relative risk, 3.3; 95% confidence interval, 1.89-5.77). Of 1284 passengers on cruise 2, 215 (17%) reported ARI, 994 (77%) were aged > or =65 years, and 336 (26%) had other risk factors for respiratory complications. An influenza strain not previously identified in North America was isolated. We concluded that an "off-season" influenza outbreak occurred among international travelers and crew on board this cruise ship.

Illness outbreak associated with Escherichia coli O157:H7 in Genoa salami. E. coli O157:H7 Working Group.

BACKGROUND: An outbreak of Escherichia coli O157:H7 infection was identified in the spring of 1998, with a 7-fold increase in the number of laboratory-confirmed E. coli O157:H7 cases in southern Ontario. This prompted an intensive investigation by local, provincial and federal public health officials. METHODS: Case interviews of 25 people from southern Ontario were conducted using a broad food history and environmental exposure survey. Laboratory investigations involved both case and food sampling. Specimens of foods sold locally and reportedly consumed by those affected were tested. Common suppliers of suspected foods were identified by cross-referencing suppliers' lists with stores frequented by those who fell ill. A case-control study involving 25 cases and 49 age-matched controls was conducted. This was followed by a comprehensive environmental investigation of the meat processing plant identified as the source of the E. coli. RESULTS: Thirty-nine outbreak-related cases occurred between April 3 and June 2, 1998. Of the 36 case specimens tested all were positive for E. coli O157:H7. The case-control study identified Genoa salami as the most probable (odds ratio 8 [confidence interval 2-35]) source of the outbreak. Samples of Genoa salami produced by the most commonly identified supplier later tested positive for E. coli O157:H7, and the pathogen matched the same pulsed-field gel electrophoresis pattern and phage type of the case specimens. INTERPRETATION: Our investigation, which led to a national recall of the brand of dry fermented Genoa salami identified as the source of the outbreak, supports an adherence to stringent manufacturing requirements for fermented meat products. A review of the Canadian standards for fermented meat processing and the effectiveness of their implementation is warranted.

A community outbreak of Salmonella berta associated with a soft cheese product.

In September 1994, a complaint was registered at a public health unit concerning a cheese product. In addition, public health laboratories in Ontario reported an increase in the number of isolates of Salmonella berta from patients with diarrhoeal illness. A clinical, environmental and laboratory investigation was initiated to determine the nature of this outbreak. Isolates of Salmonella berta were compared using large fragment genomic fingerprinting by pulsed-field gel electrophoresis (PFGE). By late October, 82 clinical cases had been identified including 35 confirmed, 44 suspected and 3 secondary. The investigation linked illness to consumption of an unpasteurized soft cheese product produced on a farm and sold at farmers' markets. Subtyping results of patient, cheese and chicken isolates were indistinguishable, suggesting that the cheese was contaminated by chicken carcasses during production. The outbreak illustrates the potential role of uninspected home-based food producers and of cross-contamination in the transmission of foodborne bacterial pathogens.