Robert F. Breiman

Effectiveness of maternal influenza immunization in mothers and infants.

BACKGROUNDnYoung infants and pregnant women are at increased risk for serious consequences of influenza infection. Inactivated influenza vaccine is recommended for pregnant women but is not licensed for infants younger than 6 months of age. We assessed the clinical effectiveness of inactivated influenza vaccine administered during pregnancy in Bangladesh.nnnMETHODSnIn this randomized study, we assigned 340 mothers to receive either inactivated influenza vaccine (influenza-vaccine group) or the 23-valent pneumococcal polysaccharide vaccine (control group). Mothers were interviewed weekly to assess illnesses until 24 weeks after birth. Subjects with febrile respiratory illness were assessed clinically, and ill infants were tested for influenza antigens. We estimated the incidence of illness, incidence rate ratios, and vaccine effectiveness.nnnRESULTSnMothers and infants were observed from August 2004 through December 2005. Among infants of mothers who received influenza vaccine, there were fewer cases of laboratory-confirmed influenza than among infants in the control group (6 cases and 16 cases, respectively), with a vaccine effectiveness of 63% (95% confidence interval [CI], 5 to 85). Respiratory illness with fever occurred in 110 infants in the influenza-vaccine group and 153 infants in the control group, with a vaccine effectiveness of 29% (95% CI, 7 to 46). Among the mothers, there was a reduction in the rate of respiratory illness with fever of 36% (95% CI, 4 to 57).nnnCONCLUSIONSnInactivated influenza vaccine reduced proven influenza illness by 63% in infants up to 6 months of age and averted approximately a third of all febrile respiratory illnesses in mothers and young infants. Maternal influenza immunization is a strategy with substantial benefits for both mothers and infants. (ClinicalTrials.gov number, NCT00142389.)

Nipah virus encephalitis reemergence, Bangladesh

Two Nipah virus encephalitis outbreaks in Bangladesh may be associated with person-to-person transmission.

Person-to-person transmission of Nipah virus in a Bangladeshi community.

Transmission of this virus highlights the need for infection control strategies for resource-poor settings.

Bacteremic Typhoid Fever in Children in an Urban Slum, Bangladesh

We confirmed a bacteremic typhoid fever incidence of 3.9 episodes/1,000 person-years during fever surveillance in a Dhaka urban slum. The relative risk for preschool children compared with older persons was 8.9. Our regression model showed that these children were clinically ill, which suggests a role for preschool immunization.

Risk factors for kala-azar in Bangladesh

Since 1990, South Asia has experienced a resurgence of kala-azar (visceral leishmaniasis). To determine risk factors for kala-azar, we performed cross-sectional surveys over a 3-year period in a Bangladeshi community. By history, active case detection, and serologic screening, 155 of 2,356 residents had kala-azar with onset from 2000 to 2003. Risk was highest for persons 3–45 years of age, and no significant difference by sex was seen. In age-adjusted multivariable models, 3 factors were identified: proximity to a previous kala-azar patient (odds ratio [OR] 25.4, 95% confidence interval [CI] 15–44 within household; OR 3.2 95% CI 1.7–6.1 within 50 m), bed net use in summer (OR 0.7, 95% CI 0.53–0.93), and cattle per 1,000 m2 (OR 0.8, 95% CI 0.70–0.94]). No difference was seen by income, education, or occupation; land ownership or other assets; housing materials and condition; or keeping goats or chickens inside bedrooms. Our data confirm strong clustering and suggest that insecticide-treated nets could be effective in preventing kala-azar.

Effect of infant immunisation on childhood mortality in rural Bangladesh: analysis of health and demographic surveillance data

BACKGROUNDnIn developing countries, immunisation programmes must compete with other strategies to improve public health and quality of life. Studies of long-term effects of immunisation programmes are rare. We assessed associations between vaccinations and mortality over 15 years after the introduction of routine infant immunisation programmes in Matlab, Bangladesh.nnnMETHODSnWe analysed data recorded in a comprehensive health and demographic surveillance system from 1986 to 2001. We did univariate analyses and assessed vaccinations as independent factors with other variables in Cox models with time dependent covariates.nnnFINDINGSnDiphtheria-tetanus-pertussis (DTP) and oral polio vaccination were independently associated with decreased risk of death before age 9 months, as were amount of maternal education, maternal age, and birth order of the child. DTP vaccination was associated with increased survival (hazard ratio=0.76, 95% CI 0.67-0.88; p=0.001) in a model evaluating mortality between 6 weeks and 9 months of age. Measles vaccination was also associated with increased survival when data after late immunisation with DTP and Bacille Calmette-Guérin (BCG) were excluded. BCG vaccination was associated with reduced survival; however, children vaccinated with BCG during the first 6 months of life had significantly lower risk of death than those vaccinated later (hazard ratio=0.59; 95% CI 0.47-0.73; p=0.0001).nnnINTERPRETATIONnBy contrast with previous findings, we noted substantially reduced mortality among children who received DTP vaccine. This effect could be due to actual protection against pertussis disease and secondary illnesses or to a non-specific benefit, although we cannot rule out epidemiological artifact. Our findings show the value of population-based health surveillance systems.

Leptospirosis during Dengue Outbreak, Bangladesh

We collected acute-phase serum samples from febrile patients at 2 major hospitals in Dhaka, Bangladesh, during an outbreak of dengue fever in 2001. A total of 18% of dengue-negative patients tested positive for leptospirosis. The case-fatality rate among leptospirosis patients (5%) was higher than among dengue fever patients (1.2%).

Successful co-administration of a human rotavirus and oral poliovirus vaccines in Bangladeshi infants in a 2-dose schedule at 12 and 16 weeks of age.

Co-administration of oral live-attenuated human rotavirus vaccine RIX4414 (Rotarix) and oral polio vaccine (OPV) was assessed. Healthy infants were randomised to receive 2-doses of either: RIX4414 or placebo co-administered with OPV (12 and 16 weeks of age); or RIX4414 or placebo given 15 days after OPV. After vaccination, 56.5-66.7% of RIX4414 and 18.6% of placebo recipients had seroconverted for rotavirus IgA. No significant differences between RIX4414 groups with or without OPV co-administration were observed. No statistically significant differences were observed between groups for polio seroprotection rates. RIX4414 vaccine was immunogenic when co-administered with OPV and did not interfere with OPV seroprotection rates.

Identification of In Vivo-Induced Bacterial Protein Antigens during Human Infection with Salmonella enterica Serovar Typhi

ABSTRACT We applied an immunoscreening technique, in vivo-induced antigen technology (IVIAT), to identify immunogenic bacterial proteins expressed during human infection with Salmonella enterica serovar Typhi, the cause of typhoid fever. We were able to assign a functional classification to 25 of 35 proteins identified by IVIAT. Of these 25, the majority represent proteins with known or potential roles in the pathogenesis of S. enterica. These include proteins implicated in fimbrial structure and biogenesis, antimicrobial resistance, heavy metal transport, bacterial adhesion, and extracytoplasmic substrate trafficking as well as secreted hydrolases. The 10 remaining antigens represent proteins with unknown functions. Of the 35 identified antigens, four had no immunoreactivity when probed with control sera from individuals never exposed to serovar Typhi organisms; these four included PagC, TcfB, and two antigens of unknown function encoded by STY0860 and STY3683. PagC is a virulence factor known to be upregulated in vivo in S. enterica serovar Typhimurium infection of mice. TcfB is the major structural subunit of a fimbrial operon found in serovar Typhi with no homolog in serovar Typhimurium organisms. By examining differential immunoreactivities in acute- versus convalescent-phase human serum samples, we found specific anti-PagC and anti-TcfB immunoglobulin G responses in patients with serovar Typhi bacteremia. Serovar Typhi antigens identified by IVIAT warrant further evaluation for their contributions to pathogenesis, and they may have diagnostic, therapeutic, or preventive uses.

The economic impact of visceral leishmaniasis on households in Bangladesh.

Objectivesu2002 To explore current patterns of diagnosis and treatment, quantify household economic impact and identify household strategies to cover the costs of visceral leishmaniasis (VL) care in rural Bangladesh.