Passage from India: an outbreak of hepatitis B linked to a patient who acquired infection from health care overseas.

OBJECTIVES: To investigate a nosocomial and community outbreak of hepatitis B to establish how the infections might have occurred. STUDY DESIGN: Descriptive study. METHODS: Four cases of hepatitis B who had stayed in hospital during their incubation periods, a case in one of their household contacts, and three further cases in the community were all linked to a patient who had been infected during a renal transplant in India. Medical records from cases were reviewed to extract information about risk factors for infection. Working practices were reviewed to determine how nosocomial transmissions might have occurred. 'Look-back' exercises were conducted to identify and follow-up other patients and staff who might also be at-risk of infection. Hepatitis B viral sequences from all cases were examined to determine whether they were related. RESULTS: Viral DNA sequences from all nine cases were identical. The primary case had an extremely high viral load due to underlying immunosuppression. Three of the nosocomial transmissions occurred whilst the primary and secondary cases shared general medical wards; two whilst the primary case was in standard isolation. No clear routes of infection were identified. The fourth was associated with a failure of infection control in operating theatres. CONCLUSIONS: Invasive medical procedures in high-prevalence countries carry a clear risk of blood borne viral infections. There is a need for much better awareness of this risk, both among patients who are considering travelling for treatment, and the health professionals who will be caring for them on their return. Infections may be preventable through hepatitis B vaccination. Patients admitted to hospital following invasive medical procedures in high-prevalence countries should be nursed with stringent infection control measures until blood borne viral infections can be excluded. However, patients with hepatitis B who are highly infectious may transmit the virus despite high standards of infection control.

Effectiveness of an influenza vaccine programme for care home staff to prevent death, morbidity, and health service use among residents: cluster randomised controlled trial.

OBJECTIVE: To determine whether vaccination of care home staff against influenza indirectly protects residents. DESIGN: Pair matched cluster randomised controlled trial. SETTING: Large private chain of UK care homes during the winters of 2003-4 and 2004-5. PARTICIPANTS: Nursing home staff (n=1703) and residents (n=2604) in 44 care homes (22 intervention homes and 22 matched control homes). INTERVENTIONS: Vaccination offered to staff in intervention homes but not in control homes. MAIN OUTCOME MEASURES: The primary outcome was all cause mortality of residents. Secondary outcomes were influenza-like illness and health service use in residents. RESULTS: In 2003-4 vaccine coverage in full time staff was 48.2% (407/884) in intervention homes and 5.9% (51/859) in control homes. In 2004-5 uptake rates were 43.2% (365/844) and 3.5% (28/800). National influenza rates were substantially below average in 2004-5. In the 2003-4 period of influenza activity significant decreases were found in mortality of residents in intervention homes compared with control homes (rate difference -5.0 per 100 residents, 95% confidence interval -7.0 to -2.0) and in influenza-like illness (P=0.004), consultations with general practitioners for influenza-like illness (P=0.008), and admissions to hospital with influenza-like illness (P=0.009). No significant differences were found in 2004-5 or during periods of no influenza activity in 2003-4. CONCLUSIONS: Vaccinating care home staff against influenza can prevent deaths, health service use, and influenza-like illness in residents during periods of moderate influenza activity. TRIAL REGISTRATION: National Research Register N0530147256.

The effectiveness of the mumps component of the MMR vaccine: a case control study.

In 1998/1999, an outbreak of mumps occurred among children of a religious community in North East London. A case control study was conducted to assess the effectiveness of the mumps component of the MMR vaccine. One hundred and sixty-one cases of mumps were identified and 192 controls were selected. Fifty-one percent of cases and 77% of controls had a history at least one MMR vaccination. The observed effectiveness of any MMR vaccination adjusted for age, sex and general practice was 69% (95% CI: 41-84%). This is consistent with the results of other observational studies of mumps containing vaccines, but lower than the immunogenicity of mumps vaccines reported by clinical trials. This discrepancy is because observational studies tend to underestimate vaccine effectiveness, and because immunogenicity is not necessarily an accurate biological marker of vaccine effectiveness. Two doses of vaccine were more effective (88% (95% CI: 62-96%)) than a single dose (64% (95% CI: 40-78%)). The current two-dose vaccination programme remains the best method for controlling mumps infection in the community.