Impact of COVID-19 pandemic on routine immunization.

The current COVID-19 global pandemic continues to impact healthcare services beyond those directly related to the management of SARS-CoV-2 transmission and disease. We reviewed the published literature to assess the pandemic impact on existing global immunization activities and how the impact may be addressed. Widespread global disruption in routine childhood immunization has impacted a majority of regions and countries, especially in the initial pandemic phases. While data indicate subsequent recovery in immunization rates, a substantial number of vulnerable people remain unvaccinated. The downstream impact may be even greater in resource-limited settings and economically poorer populations, and consequently there are growing concerns around the resurgence of vaccine-preventable diseases, particularly measles. Guidance on how to address immunization deficits are available and continue to evolve, emphasizing the importance of maintaining and restoring routine immunization and necessary mass vaccination campaigns during and after pandemics. In this, collaboration between a broad range of stakeholders (governments, industry, healthcare decision-makers and frontline healthcare professionals) and clear communication and engagement with the public can help achieve these goals.Key messagesThe COVID-19 pandemic has a substantial impact on essential immunization activities.Disruption to mass vaccination campaigns increase risk of VPD resurgence.Catch-up campaigns are necessary to limit existing shortfalls in vaccine uptake.Guidance to mitigate these effects continues to evolve.

Long-term Immunogenicity and Safety of the AS04-adjuvanted Human Papillomavirus-16/18 Vaccine in Four- to Six-year-old Girls: Three-year Follow-up of a Randomized Phase III Trial.

BACKGROUND: The burden of human papillomavirus (HPV) diseases is high in Latin America. HPV vaccines licensed from 2006 onwards offer protection against most HPV-related cancers, especially when introduced into national immunization programs. Barriers to optimal vaccine uptake are, however, lowering the impact of adolescent HPV vaccination programs. Immunization of children might overcome these barriers and be a strategy of choice for some countries. METHODS: This multicenter phase III randomized, controlled, single-blind study (NCT01627561) was conducted in Colombia, Mexico and Panama to assess safety and immunogenicity of 2-dose vaccination with AS04-adjuvanted HPV-16/18 vaccine in girls 4-6 years of age. We report safety outcomes and anti-HPV-16/18 antibody titers measured by enzyme-linked immunosorbent assay in HPV-vaccinated girls that were followed over a 36-month period. RESULTS: Over 36 months (ie, 30 months after the second vaccine dose), among 74 girls included in the HPV group, 1 serious adverse event unrelated to vaccination has been reported. No withdrawal because of (serious) adverse events has been reported. At month 36, all girls in the per-protocol-cohort were still seropositive for anti-HPV-16 and anti-HPV-18 with geometric mean concentrations of 1680.6 and 536.4 enzyme-linked immunosorbent assay units/mL, respectively. CONCLUSIONS: The AS04-adjuvanted HPV-16/18 vaccine administered according to a 2-dose schedule to girls 4-6 years of age induced a high and sustained immunologic response with an acceptable safety profile during the 30 months following vaccination.

Understanding the unique characteristics of seasonal influenza illness to improve vaccine uptake in the US.

Seasonal influenza results in substantial morbidity, mortality and socio-economic burden. The US Advisory Committee on Immunization Practices recommends vaccination of everyone over 6 months of age, but coverage remains substantially below the Healthy People 2020 target of 70% in most age groups. Influenza is different from other vaccine-preventable diseases in several ways that influence vaccine uptake. Although the incidence of most vaccine-preventable diseases is low, there is a perception that these diseases result in significant illness or death. In contrast, seasonal influenza has a relatively high incidence, but there is an incorrect perception of a lower disease severity. The vaccine effectiveness of seasonal influenza vaccines is less than other routine vaccines, varies from season to season between northern and southern hemispheres, and can be low in some seasons. It is also not well recognized that vaccination can attenuate the severity of influenza illness. Finally, the need for annual vaccination is perceived as a burden to busy people. Understanding these differences from the perspective of caregivers and vaccinees might help to improve influenza vaccine uptake. Presenting vaccine effectiveness in terms of clinical outcomes that have the most impact might help to overcome the perceptions that influenza is a non-serious disease and that the vaccine is not effective. The benefits of disease attenuation need to be emphasized in terms of reduced mortality, hospitalization, absenteeism and disruption to daily life. Innovative communication strategies should be adopted, including stronger recommendations from and to healthcare providers, continuous patient education, and social media initiatives employing more emotional and narrative approaches than traditionally used. Finally, access to seasonal influenza vaccination needs to be improved, and barriers such as cost and inconvenience removed. Multiple initiatives have already been successful. The remaining challenge is to translate individual successes into public health policies with corresponding funding and implementation.

The burden of influenza A and B in Mexico from the year 2010 to 2013: An observational, retrospective, database study, on records from the Directorate General of Epidemiology database.

Despite vaccination programs, influenza still represents a significant disease burden in Mexico. We conducted an observational, retrospective analysis to better understand the epidemiological situation of the influenza virus in Mexico. Analysis of the seasonal patterns of influenza A and B were based on the Directorate General of Epidemiology dataset of influenza-like illness(ILI), and severe acute respiratory infection(SARI) that were recorded between January 2010 and December 2013. Our objectives were 1) to describe influenza A and B activity, by age group, and subtype and, 2) to analyze the number of laboratory-confirmed cases presenting with ILI by influenza type, the regional distribution of influenza, and its clinical features. Three periods of influenza activity were captured: August 2010-January 2011, December 2011-March 2012, and October 2012-March 2013. Cases were reported throughout Mexico, with 50.3% (n = 10,320) of cases found in 18-49 year olds. Over the entire capture period, a total of 76,085 ILI/SARI episodes had swab samples analyzed for influenza, 27% were positive. During the same period, influenza A cases were higher in the 18-49 years old, and influenza B cases in both 5-17 and 18-49 age groups. Peak activity occurred in January 2012 (n = 4,159) and December 2012 (n = 348) for influenza A and B respectively. This analysis confirms that influenza is an important respiratory pathogen for children and adults in Mexico despite vaccination recommendations. School-age children and adolescents were more prone to influenza B infection; while younger adults were susceptible to both influenza A and B viruses. Over the seasons, influenza A and B co-circulated.

Safety and Immunogenicity of the HPV-16/18 AS04-adjuvanted Vaccine in 4-6-year-old Girls: Results to Month 12 From a Randomized Trial.

BACKGROUND: The burden of cervical cancer caused by human papillomavirus (HPV) is high in Latin America. The suboptimal HPV vaccination coverage in adolescents could be improved by pediatric immunization. HPV vaccination has not yet been reported in girls <9 years of age. METHODS: This ongoing phase III, controlled, randomized, single-blind, multicenter study conducted in Colombia, Mexico and Panama (NCT01627561) evaluated the safety and immunogenicity of AS04-HPV-16/18 vaccine in 4-6-year-old girls. Healthy girls (randomized 1:1) received either 2 doses of AS04-HPV-16/18 vaccine (HPV group, N=74) or 1 dose of each measles-mumps-rubella and diphtheria-tetanus-acellular-pertussis vaccines (control group, N=74) 6 months apart. We report the safety and serum anti-HPV-16 and anti-HPV-18 antibodies (measured by enzyme-linked immunosorbent assay) up to 6 months postvaccination, that is, month (M) 12. RESULTS: Injection site pain was the most frequently reported solicited local symptom in HPV vaccinees. The incidence of other solicited and unsolicited symptoms after each vaccination was similar between the HPV and control group. Until M12, 1 girl in the HPV group and 2 in the control group reported serious adverse events; all serious adverse events were assessed as unrelated to study vaccines. No potential immune-mediated diseases were identified. All girls seroconverted for both antigens after 2 doses of AS04-HPV-16/18. In initially seronegative girls, anti-HPV-16 geometric mean concentrations were 20080.0 enzyme-linked immunosorbent assay units (EU)/mL at M7 and 3246.5 EU/mL at M12; anti-HPV-18 geometric mean concentrations were 10621.8 EU/mL at M7 and 1216.6 EU/mL at M12. CONCLUSIONS: Two-dose vaccination with AS04-HPV-16/18 was well tolerated and induced adequate antibody responses in 4-6-year-old girls.

Health economic assessment of universal immunization of toddlers against Hepatitis A Virus (HAV) in Mexico.

Hepatitis A virus (HAV) has shifted from high to intermediate endemicity in Mexico, which may increase the risk of clinically significant HAV infections in older children, adolescents and adults. The objective of this study was to evaluate the cost-utility of single-dose or 2-dose universal infant HAV vaccination strategy in Mexico, compared with no vaccination. A previously published dynamic model estimated the expected number of HAV cases with each strategy, and a decision model was used to estimate the costs and quality-adjusted life-years (QALYs) expected with each strategy. The time horizon was 25 years (2012-2036) and the base case analysis was conducted from the perspective of the Mexican public health system. Costs and QALYs after the first year were discounted at 5% annually. Input data were taken from national databases and published sources where available. The single-dose HAV vaccination strategy had an incremental cost-utility ratio (ICUR) of Mexican peso (MXN) 2,270 per QALY gained, compared with no vaccination. The two-dose strategy had an ICUR of MXN 14,961/QALY compared with no vaccination, and an ICUR of MXN 78,280/QALY compared with the single-dose strategy. The estimated ICURs were below the threshold of 1 x Mexican gross domestic product per capita. When indirect costs were included (societal perspective), the single-dose HAV vaccination strategy would be expected to improve health outcomes and to be cost-saving. This analysis indicates that routine vaccination of toddlers against HAV would be cost-effective in Mexico using either a single-dose or a 2-dose vaccination strategy. GSK study identifier: HO-12-12877.

Seroprevalences of varicella-zoster virus, herpes simplex virus and cytomegalovirus in a cross-sectional study in Mexico.

We estimated the seroprevalences of varicella-zoster virus (VZV), herpes simplex virus (HSV) and cytomegalovirus (CMV) in this cross-sectional database study. Serum samples collected during the National Health and Nutrition survey (ENSANUT 2006) were obtained from subjects aged 1-70 years between January and October 2010. Serological assays for the determination of antibodies against VZV, HSV and CMV were performed. The overall seroprevalences of VZV, HSV-1, HSV-2 and CMV were 85.8%, 80.9%, 9.9% and 89.2%, respectively. Seroprevalences of VZV, HSV-1 and CMV were comparable between males and females. For HSV-2, although the seroprevalence rate was higher in females when compared to males, this difference in seroprevalence was not statistically significant. Seroprevalence rates for VZV, HSV-1, HSV-2 and CMV increased with age (p-value<.0001). Differences in seroprevalence rate for VZV by socioeconomic status (SES) were significant (p-value<0001). Results of the serological analyses reported high VZV seroprevalence, indicating high transmission in the Mexican population with children and adolescents at risk of acquiring VZV. Global HSV-1 seroprevalence was high, especially in adults. HSV-1 and HSV-2 seroprevalences were consistently higher in women than men, particularly for HSV-2. CMV seroprevalence was higher in Mexico when compared to developed countries. Seroepidemiological data on VZV supports the fact that varicella vaccination may serve as an alternative effective solution to reduce transmission in the Mexican population. For CMV and HSV, since no vaccines are available, activities to reduce transmission are important to reduce the risk of complications and therefore need to be considered.

Seroprevalence of hepatitis A virus in a cross-sectional study in Mexico: Implications for hepatitis A vaccination.

Hepatitis A virus (HAV) remains a public health concern worldwide contributing to significant morbidity in developed and developing countries. This cross-sectional database study estimated the overall HAV seroprevalence and the seroprevalence by gender, age, region and socioeconomic status in Mexico. Between January and October 2010, serum samples collected during the National Health and Nutrition survey (ENSANUT 2006) were obtained from subjects aged 1-95 y. Subjects' gender, age, geographical region and socioeconomic status were extracted from the survey and compiled into a subset database by the Mexican National Institute of Public Health. Anti-HAV antibodies were measured using a chemiluminescent immunoassay. A total of 3658 subjects were included in the according-to-protocol cohort. Overall, the HAV seroprevalence was 84.2%. The HAV seroprevalence rates were similar between females (86.1%) and males (82.2%). The percentage of subjects seropositive for anti-HAV antibodies was highest in adults aged ≥ 20 y (96.9%), followed by adolescents aged 10-19 y (80.1%) and lowest in children aged 1-9 y (45.0%) (p < 0.0001). Regionally, the highest HAV seroprevalence rate was observed in the South (88.8%) followed by Central and Northern Mexico and Mexico City (p = 0.02). The HAV seroprevalence was similar between subjects of high socioeconomic (90.1%) status and of low socioeconomic status (86.6%). This study confirms the intermediate HAV endemicity in Mexico. Cost-effectiveness studies are necessary to evaluate the inclusion of an effective hepatitis A vaccine from a population-based perspective in addition to continuous efforts to improve hygiene and sanitation that have a substantial impact on the disease burden.

Model-based projections of the population-level impact of hepatitis A vaccination in Mexico.

There are indications of a shift in the pattern of hepatitis A (HAV) in Mexico from high to intermediate endemicity, progressively increasing the mean age of infection and the proportion of cases which are symptomatic. This study estimated the potential impact of universal infant HAV vaccination in Mexico with two doses of Havrix™ at 12 and 18 mo of age on all HAV infections and symptomatic HAV infections. We developed a dynamic transmission model that accounts for changes in demography and HAV epidemiology. It was calibrated using Mexican age-specific seroprevalence and symptomatic HAV incidence data. With 70% first-dose coverage and 85% second-dose coverage, the calibrated model projected that HAV vaccination would reduce the incidence of all HAV infections (symptomatic and asymptomatic) after the first 25 y of vaccination by 71-76% (minimum and maximum for different transmission scenarios). The projected reduction in cumulative incidence of symptomatic HAV infections over the first 25 y of vaccination was 45-51%. With 90% first-dose coverage and 85% second-dose coverage, the projected reduction in incidence of all HAV infections was 85-93%, and the projected reduction in the cumulative incidence of symptomatic HAV infections was 61-67%, over a 25-y time frame. Sensitivity analyses indicated that second-dose coverage is important under the conservative base-case assumptions made about the duration of vaccine protection. The model indicated that universal infant HAV vaccination could substantially reduce the burden of HAV disease in Mexico.

[Consensus on the clinical and microbiologic diagnosis of Bordetella pertussis, and infection prevention. Expert Group on Pertussis Vaccination]. / Consenso para el diagnóstico clínico y microbiológico y la prevención de la infección por Bordetella pertussis. Grupo de expertos en vacunación contra tos ferina.

Pertussis continues to be responsible for a significant disease burden worldwide. Although immunization practices have reduced the occurrence of the disease among children, waning vaccine- and infection-induced immunity still allows the disease to affect adolescents and adults who, in turn, can transmit the disease to non-immunized or partially immunized infants. This document is the result of a meeting in Mexico City of international experts who analyzed recent medical information in order to establish the current status of the epidemiology, diagnosis and surveillance of pertussis and, especially, the value of the dTpa booster dose in adolescents and adults as a pertussis prevention strategy in Mexico.

Consenso para el diagnóstico clínico y microbiológico y la prevención de la infección por Bordetella pertussis / Consensus on the clinical and microbiologic diagnosis of Bordetella pertussis, and infection prevention

La tos ferina sigue siendo responsable de una carga de enfermedad importante en el mundo. Aunque la implementación del uso de la vacuna contra esta enfermedad ha disminuido en gran medida el número de casos en la población pediátrica, se ha observado que la inmunidad inducida por la vacuna y por la infeccion natural disminuye con el tiempo lo que hace nuevamente susceptibles a adolescentes y adultos jóvenes que pueden transmitir la enfermedad a lactantes no inmunizados o con esquema de vacunación incompleto. Este documento, resultado de la reunión de un grupo internacional de expertos en la Ciudad de México, ha analizado la información médica reciente para establecer el estado actual de la epidemiología, diagnóstico, vigilancia y, especialmente, el valor de la dosis de refuerzo con dTpa en adolescentes y adultos como estrategia de prevención de tos ferina en México.

Pertussis continues to be responsible for a significant disease burden worldwide. Although immunization practices have reduced the occurrence of the disease among children, waning vaccine- and infection-induced immunity still allows the disease to affect adolescents and adults who, in turn, can transmit the disease to non-immunized or partially immunized infants. This document is the result of a meeting in Mexico City of international experts who analyzed recent medical information in order to establish the current status of the epidemiology, diagnosis and surveillance of pertussis and, especially, the value of the dTpa booster dose in adolescents and adults as a pertussis prevention strategy in Mexico.

Patrón de la enfermedad y sobrevida en niños y adolescentes infectados por VIH manejados con terapia antirretroviral altamente activa / Trends and survival in HIV-infected children and adolescents management with highly active antiretroviral therapy

Introducción. Después de la introducción del tratamiento antirretroviral altamente activo (TARAA), la sobrevida y la calidad de vida de las personas infectadas por el virus de inmunodeficiencia humana (VIH), incluyendo los niños y adolescentes, han mejorado sustancialmente. Métodos. El presente estudio se realizó en una cohorte de niños infectados por VIH, menores de 18 años de edad, que asistieron a la Clínica de Inmunodeficiencias/VIH del Hospital Infantil de México Federico Gómez de abril de 1989 a diciembre de 2008. De los expedientes clínicos se obtuvieron: datos sociodemográficos, eventos infecciosos, hospitalizaciones y defunciones. Resultados. Se incluyeron 202 pacientes infectados por el VIH con o sin TARAA. El promedio de edad al diagnóstico de síndrome de inmunodeficiencia adquirida fue de 37.3 meses. La transmisión perinatal fue la más frecuente con 96%. Al diagnóstico de VIH la mayoría cursaba con enfermedad avanzada. La tasa de incidencia de infecciones oportunistas antes del diagnóstico fue de 30.2/100 pacientes/año, mientras que posterior al TARAA disminuyó a 3.3; 95% de los pacientes que recibieron TARAA tuvieron una sobrevida de 10 años en promedio. Conclusiones. Con la administración del TARAA se observó disminución de eventos infecciosos, hospitalizaciones y mortalidad en la población estudiada.

Introduction. Since the introduction of highly active antiretroviral therapy (HAART), quality of life and survival of those persons infected by HIV, including children and adolescents, have improved substantially. Methods. This case study focuses on children <18 years old who were seen from April 1989 to December 2008 at the Immunodeficiency Clinic of the Hospital Infantil de Mexico Federico Gomez. Demographic data, infections, admissions and deaths were gathered. Results. 202 HIV-infected children and adolescents were seen under HAART or without HAART (>6 months). Of all patients, the time since diagnosis of acquired immunodeficiency syndrome (AIDS) was on average 37.3 months. Perinatal transmission was the most frequent mode in 96%. At diagnosis of AIDS, most patients were in an advanced stage of illness. The incidence rates of opportunistic infections decrease from 30.2 episodes per 100 person-years before HAART to 3.3 after initiation of HAART. Of patients receiving HAART, 95% had a survival >10 years. Conclusions. Management with HAART decreased incidence rates of infectious diseases, admissions and death in the population studied.

Respuesta discordante a terapia antirretroviral altamente activa en pacientes pediátricos mexicanos infectados con VIH/SIDA / Discordant response to highly active antiretroviral therapy in Mexican pediatric patients infected with HIV/AIDS

Introducción. El objetivo de la terapia antirretroviral es lograr un descenso rápido de la carga viral y un aumento en el recuento de las células CD4- Sin embargo, en la respuesta discordante sólo se cumple uno de los objetivos de la terapia: disminución de la carga viral o aumento de linfocitos CD4. Métodos. Estudio retrospectivo de pacientes pediátricos que acuden a la Clínica de Inmunodeficiencias del Hospital Infantil de México Federico Gómez. La respuesta inmunológica/virológica a terapia antirretroviral se clasificó en 4 clases: óptima, falla, respuesta discordante con éxito viral y respuesta discordante con fracaso viral. Se analizaron los datos demográficos y las determinaciones de carga viral y cuenta de linfocitos CD4 al ingreso, a los 6 y 12 meses posteriores al inicio del tratamiento. Resultados. Se analizaron 56 pacientes, con edad promedio a su ingreso de 30.5 meses. La frecuencia de respuesta discordante al tratamiento, después de 6 y 12 meses fue de 45 y 53.5%, respectivamente. Conclusión. La respuesta discordante en nuestra población pediátrica es mayor de 50%, similar a lo reportado en otros estudios pediátricos. A pesar de ser un escenario común, la repercusión clínica aún es incierta, por lo que este tipo de respuesta no debe de interpretarse, en primera instancia, como una mala respuesta a la terapia antirretroviral.

Introduction. The goal of antiretroviral (ART) therapy is to control human immunodeficiency virus replication and to increase CD4 T-cell count. Discordant response to ART occurs when only one of these two objectives is achieved. Methods. Pediatric patients who attended the Clínica de Inmunodeficiencias at Hospital Infantil de Mexico Federico Gomez were studied retrospectively. Response to a Pibased highly active antiretroviral therapy (HAART) was classified as optimal, failure, discordant response with viral failure and discordant response with viral success. Demographic data, viral load and CD4 T-cell count (baseline, 6-month and 12-month follow-up determinations) were analyzed. Results. Fifty six patients were included. Mean age of patients was 30.5 months. Discordant response was seen in 45 and 53.5% at 6- and 12-months follow-up, respectively. Conclusions. Discordant response was seen in >50% of our study population and is a common scenario; clinical implications are still unknown. Discordant response should not be interpreted, especially during the first 12 months of therapy, as a failure of HAART.

Brote de bacteriemia nosocomial y colonización por Serratia marcescens en una Unidad de Cuidado Intensivo Neonatal / Nosocomial bacteremia and gastrointestinal tract colonization outbreak of Serratia marcescens in Neonatal Intensive Care Unit

Introducción. Se presenta la descripción de un brote de bacteriemia y colonización gastrointestinal nosocornial por Serratia marcescens en una Unidad de Cuidado Intensivo Neonatal (UCIN) de un hospital de tercer nivel. Material y métodos. El período epidémico fue considerado del 17 de mayo al 17 de junio de 2006. Se definió como caso a cualquier paciente con cultivo positivo para S. marcescens durante el período epidémico, ya que no se había identificado ningún cultivo positivo para esta bacteria en 6 meses de período pre-epidémico. Para identificar factores de riesgo de desarrollo de infección/colonización por S. mareescens, se compararon los casos con pacientes controles, definidos como aquéllos expuestos durante el período del brote sin aislamiento de esta bacteria. Todos los aislamientos de microorganismos fueron genotipificados por restricción con endonucleasa y electroforesis en gel por campos pulsados (PFGE). Resultados. Durante el período epidémico se identificaron 7 pacientes con cultivos positivos para S. marcescens y 12 controles. El paciente índice tuvo hemocultivo positivo y cuadro clínico de bacteriemia nosocomial, seguido por un caso de ventriculitis con cultivo positivo para S. marcescens en líquido cefalorraquídeo. Los otros 5 casos tuvieron aislamiento de S. marcescens en coprocultivos. Los cultivos de soluciones intravenosas y superficies inanimadas fueron negativos. El análisis univariado demostró que los pacientes con infección/colonización por S. marcescens tuvieron una estancia hospitalaria más prolongada (52 vs 27.9 días, P < 0.05), mayor frecuencia de alimentación enteral y presencia de sonda orogástrica al compararse con los controles. El patrón de PFGE fue idéntico en todos los aislamientos de S. mareescens. El reforzamiento de precauciones de contacto, incluyendo lavado de manos, además de cierre temporal de la UCIN, controló el problema de brote. Conclusión. El análisis epidemiológico complementado con técnicas de epidemiología molecular en este estudio aporta evidencia de un brote de 2 casos de bacteriemia nosocomial por transmisión cruzada de S. marcescens a través de un reservorio gastrointestinal. Estos hallazgos confirman la importancia que tienen las medidas de precauciones de contacto como el lavado de manos en el manejo de pacientes de la UCIN para prevenir infecciones nosocomiales y control de brotes.

Introduction. We investigated an outbreak of Serratia marcescens bloodstream infection (BSI)/colonization in patients from a Neonatal Intensive Care Unit (NICU) in a tertiary care pediatric Hospital. Material and methods. May 17 through June 17, 2006 was considered as the study period. A case was defined as any patient with S. marcescens-positive culture in the NICU during the outbreak period because no S. marcescens was identified in this area within 6 month of pre-epidemic period. To identify risk factors we compared patients with S. marcescens positive-cultures with controls exposed to the cases during the outbreak period without positive cultures. Genotyping of all S. marcescens isolates were evaluated by restriction endonuclease and pulsed-field gel electrophoresis (PFGE). Results. Seven S. marcescens positive cultures were identified; the index case had a positive blood culture with diagnosis of BSI, followed by a patient with CSF positive culture with diagnosis of ventriculitis and BSI. The remaining 5 cases had concurrent S. marcescens isolates from stool cultures (colonization). Environmental cultures (water, IV solutions and inanimate surfaces) were negative for these bacteria. According to univariate analysis, patients with S. marcescens stayed in the NICU longer than controls (52 vs 27.9 days, P < 0.05), they were more likely to have an orogastric tube in place and to receive enteral nutrition. All the S. marcescens had an identical pattern of PFGE analysis. Contact precaution, including hand washing, was reinforced in addition to temporary closing of the NICU in order to control the outbreak. Conclusions. This outbreak of S. marcescens was studied using epidemiological analysis and molecular biology techniques, confirming cross-transmission between cases associated to a possible gastrointestinal reservoir. Our findings underscore the importance of hand hygiene and other contact precaution methods in hospital settings, such as NICU.