Minal K. Patel

Serial Intervals and the Temporal Distribution of Secondary Infections within Households of 2009 Pandemic Influenza A (H1N1): Implications for Influenza Control Recommendations

A critical issue during the 2009 influenza A (H1N1) pandemic was determining the appropriate duration of time individuals with influenza-like illness (ILI) should remain isolated to reduce onward transmission while limiting societal disruption. Ideally this is based on knowledge of the relative infectiousness of ill individuals at each point during the course of the infection. Data on 261 clinically apparent pH1N1 infector-infectee pairs in households, from 7 epidemiological studies conducted in the United States early in 2009, were analyzed to estimate the distribution of times from symptom onset in an infector to symptom onset in the household contacts they infect (mean, 2.9 days, not correcting for tertiary transmission). Only 5% of transmission events were estimated to take place >3 days after the onset of clinical symptoms among those ill with pH1N1 virus. These results will inform future recommendations on duration of isolation of individuals with ILI.

An Outbreak of Wild Poliovirus in the Republic of Congo, 2010–2011

BACKGROUND The Republic of Congo has had no cases of wild poliovirus type 1 (WPV1) since 2000. In October 2010, a neurologist noted an abnormal number of cases of acute flaccid paralysis (AFP) among adults, which were later confirmed to be caused by WPV1. METHODS Those presenting with AFP underwent clinical history, physical examination, and clinical specimen collection to determine if they had polio. AFP cases were classified as laboratory-confirmed, clinical, or nonpolio AFP. Epidemiologic features of the outbreak were analyzed. RESULTS From 19 September 2010 to 22 January 2011, 445 cases of WPV1 were reported in the Republic of Congo; 390 cases were from Pointe Noire. Overall, 331 cases were among adults; 378 cases were clinically confirmed, and 64 cases were laboratory confirmed. The case-fatality ratio (CFR) was 43%. Epidemiologic characteristics differed among polio cases reported in Pointe Noire and cases reported in the rest of the Republic of Congo, including age distribution and CFR. The outbreak stopped after multiple vaccination rounds with oral poliovirus vaccine, which targeted the entire population. CONCLUSIONS This outbreak underscores the need to maintain high vaccination coverage to prevent outbreaks, the need to maintain timely high-quality surveillance to rapidly identify and respond to any potential cases before an outbreak escalates, and the need to perform ongoing risk assessments of immunity gaps in polio-free countries.

Transmission of 2009 Pandemic Influenza A (H1N1) Virus among Healthcare Personnel—Southern California, 2009

OBJECTIVE In April 2009, 2009 pandemic influenza A (H1N1) (hereafter, pH1N1) virus was identified in California, which caused widespread illness throughout the United States. We evaluated pH1N1 transmission among exposed healthcare personnel (HCP) and assessed the use and effectiveness of personal protective equipment (PPE) early in the outbreak. DESIGN Cohort study. SETTING Two hospitals and 1 outpatient clinic in Southern California during March 28-April 24, 2009. PARTICIPANTS Sixty-three HCP exposed to 6 of the first 8 cases of laboratory-confirmed pH1N1 in the United States. METHODS Baseline and follow-up questionnaires were used to collect demographic, epidemiologic, and clinical data. Paired serum samples were obtained to test for pH1N1-specific antibodies by microneutralization and hemagglutination-inhibition assays. Serology results were compared with HCP work setting, role, and self-reported PPE use. RESULTS Possible healthcare-associated pH1N1 transmission was identified in 9 (14%) of 63 exposed HCP; 6 (67%) of 9 seropositive HCP had asymptomatic infection. The highest attack rates occurred among outpatient HCP (6/19 [32%]) and among allied health staff (eg, technicians; 8/33 [24%]). Use of mask or N95 respirator was associated with remaining seronegative (P = .047). Adherence to PPE recommendations for preventing transmission of influenza virus and other respiratory pathogens was inadequate, particularly in outpatient settings. CONCLUSIONS pH1N1 transmission likely occurred in healthcare settings early in the pandemic associated with inadequate PPE use. Organizational support for a comprehensive approach to infectious hazards, including infection prevention training for inpatient- and outpatient-based HCP, is essential to improve HCP and patient safety.

A prolonged outbreak of Salmonella Montevideo infections associated with multiple locations of a restaurant chain in Phoenix, Arizona, 2008.

An outbreak of Salmonella serotype Montevideo infections associated with multiple locations of restaurant chain A in Phoenix, AZ, was identified in July 2008. One infected individual reported eating at a chain A catered luncheon where others fell ill; we conducted a cohort study among attendees to identify the vehicle. Food and environmental samples collected at six chain A locations were cultured for Salmonella. Restaurant inspection results were compared among 18 chain A locations. Routine surveillance identified 58 Arizona residents infected with the outbreak strain. Three chain A locations, one of which catered the luncheon, were named by two or more case patients as a meal source in the week prior to illness onset. In the cohort study of luncheon attendees, 30 reported illness, 10 of which were later culture confirmed. Illness was reported by 30 (61%) of 49 attendees who ate chicken and by 0 of 7 who did not. The outbreak strain was isolated from two of these three locations from uncooked chicken in marinade, chopped cilantro, and a cutting board dedicated to cutting cooked chicken. Raw chicken, contaminated before arrival at the restaurant, was the apparent source of this outbreak. The three locations where two or more case patients ate had critical violations upon routine inspection, while 15 other locations received none. Poor hygiene likely led to cross-contamination of food and work areas. This outbreak supports the potential use of inspections in identifying restaurants at high risk of outbreaks and the need to reduce contamination of raw products at the source and prevent cross-contamination at the point of service.

Sustainability of market-based community distribution of Sprinkles in western Kenya

To evaluate the sustainability of market-based community distribution of micronutrient powders (Sprinkles(®), Hexagon Nutrition, Mumbai, India.) among pre-school children in Kenya, we conducted in August 2010 a follow-up survey, 18 months after study-related marketing and household monitoring ended. We surveyed 849 children aged 6-35 months randomly selected from 60 study villages. Nutritional biomarkers were measured by fingerstick; demographic characteristics, Sprinkles purchases and use were assessed through household questionnaires. We compared Sprinkles use, marketing efforts and biomarker levels with the data from surveys conducted in March 2007, March 2008 and March 2009. We used logistic regression to evaluate associations between marketing activities and Sprinkles use in the 2010 survey. At the 2010 follow-up, 21.9% of children used Sprinkles in the previous 7 days, compared with 64.9% in 2008 (P < 0.001). Average intake was 3.2 sachets week(-1) in 2008, 1.6 sachets week(-1) in 2009 and 1.1 sachets week(-1) in 2010 (P < 0.001). Factors associated with recent Sprinkles use in 2010 included young age [6-23 months vs. 24-35 months, adjusted odds ratio (aOR) = 1.5, P = 0.02], lowest 2 quintiles of socio-economic status (aOR = 1.7, P = 0.004), household attendance at trainings or launches (aOR = 2.8, P < 0.001) and ever receiving promotional items including free Sprinkles, calendars, cups and t-shirts (aOR = 1.7, P = 0.04). In 2010, there was increased prevalence of anaemia and malaria (P < 0.001), but not iron deficiency (P = 0.44), compared with that in 2008. Sprinkles use in 2010 was associated with decreased iron deficiency (P = 0.03). Sprinkles coverage reduced after stopping household monitoring and reducing marketing activities. Continued promotion and monitoring of Sprinkles usage may be important components to sustain the programme.

Measles Outbreak Associated with Vaccine Failure in Adults--Federated States of Micronesia, February-August 2014.

On May 15, 2014, CDC was notified of two laboratory-confirmed measles cases in the Federated States of Micronesia (FSM), after 20 years with no reported measles. FSM was assisted by the World Health Organization (WHO), the United Nations Children’s Fund (UNICEF), and CDC in investigating suspected cases, identify contacts, conduct analyses to guide outbreak vaccination response, and review vaccine cold chain practices. During February–August, three of FSM’s four states reported measles cases: Kosrae (139 cases), Pohnpei (251), and Chuuk (3). Two thirds of cases occurred among adults aged ≥20 years; of these, 49% had received ≥2 doses of measles-containing vaccine (MCV). Apart from infants aged <12 months who were too young for routine vaccination, measles incidence was lower among children than adults. A review of current cold chain practices in Kosrae revealed minor weaknesses; however, an absence of historical cold chain maintenance records precluded an evaluation of earlier problems. Each state implemented vaccination campaigns targeting children as young as age 6 months through adults up to age 57 years. The preponderance of cases in this outbreak associated with vaccine failure in adults highlights the need for both thorough case investigation and epidemiologic analysis to guide outbreak response vaccination. Routine childhood vaccination coverage achieved in recent years limited the transmission of measles among children. Even in areas where transmission has not occurred for years, maintaining high 2-dose MCV coverage through routine and supplemental immunization is needed to prevent outbreaks resulting from increased measles susceptibility in the population.

Investigation of Elevated Case-Fatality Rate in Poliomyelitis Outbreak in Pointe Noire, Republic of Congo, 2010

BACKGROUND Multiple cases of paralysis, often resulting in death, occurred among young adults during a wild poliovirus (WPV) type 1 outbreak in Pointe Noire, Republic of Congo, in 2010. We conducted an investigation to identify factors associated with fatal outcomes among persons with poliomyelitis in Pointe Noire. METHODS Polio cases were defined as acute flaccid paralysis (AFP) cases reported from 7 October to 7 December 2010 with either a stool specimen positive for WPV or clinically classified as polio-compatible. Data were obtained from medical records, hospital databases, AFP case investigation forms and, when possible, via interviews with persons with polio or surrogates using a standard questionnaire. RESULTS A total of 369 polio cases occurred in Pointe Noire between 7 October and 7 December 2010. Median age was 22 years for nonsurvivors and 18 years for survivors (P = .01). Small home size, as defined by ≤2 rooms, use of a well for drinking water during a water shortage, and age ≥15 years were risk factors for death in multivariate analysis. CONCLUSIONS Consideration should be given during polio risk assessment planning and outbreak response to water/sanitation status and potential susceptibility to polio in older children and adults. Serosurveys to estimate immunity gaps in older age groups in countries at high risk of polio importation might be useful to guide preparedness and response planning.

A strategy to increase adoption of locally-produced, ceramic cookstoves in rural Kenyan households.

BackgroundExposure to household air pollutants released during cooking has been linked to numerous adverse health outcomes among residents of rural areas in low-income countries. Improved cookstoves are one of few available interventions, but achieving equity in cookstove access has been challenging. Therefore, innovative approaches are needed. To evaluate a project designed to motivate adoption of locally-produced, ceramic cookstoves (upesi jiko) in an impoverished, rural African population, we assessed the perceived benefits of the cookstoves (in monetary and time-savings terms), the rate of cookstove adoption, and the equity of adoption.MethodsThe project was conducted in 60 rural Kenyan villages in 2008 and 2009. Baseline (n = 1250) and follow-up (n = 293) surveys and a stove-tracking database were analyzed.ResultsAt baseline, nearly all respondents used wood (95%) and firepits (99%) for cooking; 98% desired smoke reductions. Households with upesi jiko subsequently spent <100 Kenyan Shillings/week on firewood more often (40%) than households without upesi jiko (20%) (p = 0.0002). There were no significant differences in the presence of children <2 years of age in households using upesi jiko (48%) or three-stone stoves (49%) (p = 0.88); children 2–5 years of age were less common in households using upesi jiko versus three-stone stoves (46% and 69%, respectively) (p = 0.0001). Vendors installed 1,124 upesi jiko in 757 multi-family households in 18 months; 68% of these transactions involved incentives for vendors and purchasers. Relatively few (<10%) upesi jiko were installed in households of women in the youngest age quartile (<22 years) or among households in the poorest quintile.ConclusionsOur strategy of training of local vendors, appropriate incentives, and product integration effectively accelerated cookstove adoption into a large number of households. The strategy also created opportunities to reinforce health messages and promote cookstoves sales and installation. However, the project’s overall success was diminished by inequitable and incomplete adoption by households with the lowest socioeconomic status and young children present. Additional evaluations of similar strategies will be needed to determine whether our strategy can be applied equitably elsewhere, and whether reductions in fuel use, household air pollution, and the incidence of respiratory diseases will follow adoption of improved cookstoves.

Prevalence of chronic hepatitis B virus infection after implementation of a hepatitis B vaccination program among children in three provinces in Cambodia.

BACKGROUND Hepatitis B virus (HBV) is highly endemic in Cambodia with an estimated pre-vaccine hepatitis B surface antigen (HBsAg) prevalence of 9%. By 2005, a hepatitis B vaccination program was implemented to decrease infection rates in children. We conducted a serosurvey to evaluate the impact of the vaccination program in 2011. METHODS A cross-sectional two-stage cluster survey was conducted to estimate HBsAg prevalence among children born from 2006 to 2007 in three provinces: Phnom Penh (urban), Kratie (rural), and Ratanakiri (remote). Demographic data, as well as written or oral vaccination history were collected. Children were tested for HBsAg. Factors associated with undervaccination and HBsAg positivity were modeled. RESULTS Coverage of timely hepatitis B vaccine birth dose (administered at ≤ 24 h) was 55% in Phnom Penh, 36% in Kratie, and 22% in Ratanakiri. Coverage with ≥ 3 hepatitis B vaccine doses (HepB3) was 91% in Phnom Penh, 82% in Kratie, and 64% in Ratanakiri. When compared with children who were born in health facilities with a skilled birth attendant (SBA), children born at home without a SBA were more likely not to have received a timely BD (adjusted relative risk [aRR]=1.94; 95% CI=1.75-2.15) as were children born at home with an SBA (aRR=1.54; 95% CI=1.32-1.80). The proportion of children who tested positive for HBsAg was 0.33% in Phnom Penh, 1.41% in Kratie, and 3.45% in Ratanakiri. In all three provinces, children who received their first dose after 7 days of life and children who never received hepatitis B vaccine had the highest HBsAg prevalence. CONCLUSIONS Progress has been made in Cambodia in decreasing the burden of chronic HBV infection among children. Improvements in vaccination coverage will further decrease the burden of disease.

Hepatitis B vaccine stored outside the cold chain setting: a pilot study in rural Lao PDR

BACKGROUND Hepatitis B vaccine birth dose (HepB-BD) was introduced in Lao Peoples Democratic Republic (Lao-PDR) to prevent perinatal hepatitis B virus transmission. HepB-BD, which is labeled for storage between 2 and 8°C, is not available at all health facilities, because of some lack of functional cold chain; however, previous studies show that HepB-BD is stable if stored outside the cold chain (OCC). A pilot study was conducted in Lao-PDR to evaluate impact of OCC policy on HepB-BD coverage. METHODS During the six month pilot, HepB-BD was stored OCC for up to 28 days in two intervention districts and stored in cold chain in two comparison districts. In the intervention districts, healthcare workers were educated about HepB-BD and OCC storage. A post-pilot survey compared HepB-BD coverage among children born during the pilot (aged 2-8 months) and children born 1 year before (aged 14-20 months). FINDINGS In the intervention districts, 388 children aged 2-8 months and 371 children aged 14-20 months were enrolled in the survey; in the comparison districts, 190 children aged 2-8 months and 184 children aged 14-20 months were enrolled. Compared with the pre-pilot cohort, a 27% median increase in HepB-BD (interquartile range [IQR] 58%, p<0.0001) occurred in the pilot cohort in the intervention districts, compared with a 0% median change (IQR 25%, p=0.03) in comparison districts. No adverse reactions were reported. INTERPRETATION OCC storage improved HepB-BD coverage with no increase in adverse reactions. Findings can guide Lao-PDR on implementation and scale-up options of OCC policy.