Risk of Measles and Diphtheria Introduction and Transmission on Bonaire, Caribbean Netherlands, 2018.

Endemic transmission of measles has been reestablished in Venezuela, and outbreaks of diphtheria remain ongoing across Latin America (LA). Hence, a large cross-sectional population-based serosurveillance study was conducted on Bonaire, one of the Dutch Leeward Antilles, to assess specific age and population groups at risk. Participants (aged 0-90 years) donated a blood sample and completed a questionnaire (n = 1,129). Antibodies against measles and diphtheria were tested using bead-based multiplex immunoassays. Our data revealed that immunity against measles is suboptimal, especially for those aged less than 5 years from Suriname, Aruba, and former Dutch Antilles (SADA), and adolescents from LA; and against diphtheria for persons aged more than 30 years, particularly among females and residents from SADA and LA. As refugees arrive persistently, health authorities on the Dutch Leeward Antilles should be on alert to detect early cases and prevent subsequent transmission. Ultimately, there is an urgent need for serosurveillance studies in the Caribbean region.

A correlation of measles specific antibodies and the number of plasmacytoid dendritic cells is observed after measles vaccination in 9 month old infants.

Measles virus (MeV) represents one of the main causes of death among young children, particularly in developing countries. Upon infection, MeV controls both interferon induction (IFN) and the interferon signaling pathway which results in a severe host immunosuppression that can persists for up to 6 mo after infection. Despite the global biology of MeV infection is well studied, the role of the plasmacytoid dendritic cells (pDCs) during the host innate immune response after measles vaccination remains largely uncharacterized. Here we investigated the role of pDCs, the major producers of interferon in response to viral infections, in the development of adaptive immune response against MeV vaccine. We report that there is a strong correlation between pDCs population and the humoral immune response to Edmonston Zagreb (EZ) measles vaccination in 9-month-old mexican infants. Five infants were further evaluated after vaccination, showing a clear increase in pDCs at baseline, one week and 3 months after immunization. Three months postvaccination they showed increase in memory T-cells and pDCs populations, high induction of adaptive immunity and also observed a correlation between pDCs number and the humoral immune response. These findings suggest that the development and magnitude of the adaptive immune response following measles immunization is directly dependent on the number of pDCs of the innate immune response.

Observational study on immune response to yellow fever and measles vaccines in 9 to 15-month old children. Is it necessary to wait 4 weeks between two live attenuated vaccines?

BACKGROUND: The use of 2 live attenuated vaccines (LAV) is recommended to be simultaneous or after an interval of at least four weeks between injections. The primary objective of this study was to compare the humoral response to yellow fever (YF) and measles vaccines among children vaccinated against these two diseases, either simultaneously or separated by an interval of 7-28 days. SUBJECTS AND METHODS: A prospective, multicenter observational study was conducted among children aged 9-15 months. The primary endpoint was the occurrence of positive yellow fever antibodies after YF vaccine by estimating the titers of neutralizing antibodies from venous blood samples. Children vaccinated against YF 7-28 days after receiving the vaccine against measles (test group) were compared with children vaccinated the same day against these two diseases (referent group). RESULTS: Analysis was performed on 284 children. Of them, fifty-four belonged to the test group. Measles serology was positive in 91.7% of children. Neutralizing antibodies against YF were detected in 90.7% of the test group and 92.9 of the referent group (p=0.6). In addition, quantitative analysis of the immune response did not show a lower response to YF vaccination when it took place 1-28 days after measles vaccination. DISCUSSION: In 1965, Petralli showed a lower response to the smallpox vaccine when injected 4-20 days after measles vaccination. Since then, recommendations are to observe an interval of four weeks between LAV not injected on the same day. Other published studies failed to show a significant difference in the immune response to a LAV injected 1-28 days after another LAV. These results suggest that the usual recommendations for immunization with two LAV may not be correct. CONCLUSION: In low income countries, the current policy should be re-evaluated. This re-evaluation should also be applied to travelers to yellow fever endemic countries.

Panorama atual do sarampo no mundo: Risco de surtos nos grandes eventos no Brasil / Current landscape of measles in the world: risk of outbreaks in major events in Brazil

O sarampo é considerado uma das doenças infecciosas mais contagiosas do mundo (1), capaz de atingir todos os grupos etários, com risco particular em menores de cinco e naqueles entre 15 e 29 anos de idade (2), sendo uma das principais causas de morte evitáveis por vacina entre crianças (3). Frente aos recentes surtos de sarampo ocorridos no mundo, estaria o Brasil, que desde 2000 conseguiu eliminar a circulação do sarampo e na atualidade vem lidando apenas com surtos de pequena monta de casos importados, sob risco de grandes surtos durante a Copa do Mundo de 2014 e as Olimpíadas de 2016? Através de análises dos últimos surtos ocorridos em todo o mundo e pesquisa da cobertura vacinal no Brasil, os autores respondem a estas questões.

Measles is considered one of the most contagious diseases in the world (1). It’s able to reach all of age groups with particular risk in under five and 15-29 years old (2). It’s one of the main causes for evitable deaths for vaccine between children (3). According to recents measles outbreaks occurred in the world, Brazil is included in it, since 2000 has eliminated measles circulation and actually has been dealing with outbreaks of little dimension of imported cases, at risk of large outbreak during the World Cup 2014 and The Olympics Games 2016? Through analysis of the latest outbreaks ocurred all over the world and research of vaccine coverage in Brazil, the authors will answer to these questions.

Persistence of measles neutralizing antibody related to vaccine and natural infection acquired before HIV infection.

Little is known about long-lasting measles protective immunity when exposure to wild-type or vaccine measles virus precedes HIV infection. The results obtained suggest that measles immunity wanes and the lowest measles geometric mean titres (GMT) were significantly associated with measles vaccine-induced immunity in individuals that later developed HIV infection (86% prevalence, GMT 164 mIU/ml) compared to naturally induced immunity in HIV-infected adults (100% prevalence, GMT 340 mIU/ml, P = 0·0082) or non-HIV infected adults (100%, GMT 724 mIU/ml, P = 0·0001), and vaccine-induced immunity in non-HIV-infected adults (100%, GMT 347 mIU/ml, P = 0·017). The study was conducted in an area without wild-type virus circulation since 2000. The absence of virus circulating may alter the paradigm of lifelong immunity to measles virus after vaccination. As the proportion of HIV-infected individuals possessing only vaccine-induced immunity continues to grow, checking the status of measles immunity in this group is strongly recommended.

Asymmetric regression models with limited responses with an application to antibody response to vaccine.

We develop regression models for limited and censored data based on the mixture between the log-power-normal and Bernoulli-type distributions. A likelihood-based approach is implemented for parameter estimation and a small-scale simulation study is conducted to evaluate parameter recovery, with emphasis on bias estimation. The main conclusion is that the approach is very much satisfactory for moderate and large sample sizes. A real data example, the safety and immunogenecity study of measles vaccine in Haiti, is presented to illustrate how different models can be used to fit this type of data. As shown, the asymmetric models considered seem to present the best fit for the data set under study, revealing significance of the explanatory variable sex, which is not found significant with the log-normal model.

Evaluación de la seroprotección contra sarampión, rubéola y hepatitis B en niños menores de cinco años del Perú, 2011 / Evaluation of the seroprotection against measles, rubella and hepatitis B in children under 5 years of age in Peru, 2011

Objetivos. Estimar la prevalencia de anticuerpos contra sarampión, rubéola y hepatitis B en niños de 1 a 4 años del Perú. Materiales y métodos. Se realizó una encuesta nacional basada en la aplicación de un cuestionario y obtención de muestra de sangre capilar en papel de filtro para el estudio de anticuerpos contra sarampión, rubéola y hepatitis B en niños de 1 a 4 años. Se utilizó un muestreo probabilístico, estratificado y multietápico con inferencia a nivel nacional y siete ámbitos de estudio: Lima metropolitana, resto de costa urbana, costa rural, sierra urbana, sierra rural, selva urbana y selva rural. Las muestras de sangre capilar fueron procesadas siguiendo protocolos estandarizados para la determinación de anticuerpos mediante técnica de ELISA utilizando reactivos comerciales. Resultados. Se encontró una prevalencia nacional de 91,6% (IC95%: 90,6-92,7%), 91,3% (IC 95%: 90,3-92,4%) y 95,9% (IC 95%: 95,0-96,8%) para anticuerpos contra sarampión, rubéola y hepatitis B respectivamente. No se evidenció diferencias significativas de las prevalencias entre los diferentes ámbitos de estudio y en los diferentes estratos socioeconómicos de los conglomerados. Conclusiones. En niños de 1 a 4 años se ha estimado una prevalencia nacional de anticuerpos contra sarampión y rubéola entre 90-93%, mientras que para anticuerpos contra hepatitis B (anti-HBsAg) entre 95-97%.

Objectives. To estimate the prevalence of antibodies against measles, rubella and hepatitis B in children aged between 1 and 4 years in Peru. Materials and methods. A national survey was conducted based on a questionnaire and capillary blood sample taken on filter paper in order to study antibodies against measles, rubella and hepatitis B in children from 1 to 4 years of age. A stratified, multistage, probability sampling design was used to be representative at the national level and at level of seven ambits, including the Metropolitan Lima Area, the rest of the urban coast, the rural coast, the urban highlands, the rural highlands, the urban jungle and the rural jungle. The capillary blood samples were processed according to the standardized protocols for detection of antibodies using the ELISA technique and commercial reagents. Results. The survey showed a national prevalence of antibodies against measles, rubella and hepatitis B of 91.6% (CI 95%: 90.6%; 92.7%), 91.3% (CI 95%: 90.3%; 92.4%) and 95.9% (CI 95%: 95.0%; 96.8%) respectively. There was no evidence of significant differences in the prevalence among the ambits of study or among the socioeconomic strata of the conglomerates for any of the three types of antibodies. Conclusions. In children from 1 to 4 years of age, the national prevalence of antibodies against measles and Rubella was between 90-93%, while the prevalence of antibodies against Hepatitis B (anti-HBsAg) was between 95-97%.

[Evaluation of the seroprotection against measles, rubella and hepatitis B in children under 5 years of age in Peru, 2011]. / Evaluación de la seroprotección contra sarampión, rubéola y hepatitis B en niños menores de cinco años del Perú, 2011.

OBJECTIVES: To estimate the prevalence of antibodies against measles, rubella and hepatitis B in children aged between 1 and 4 years in Peru. MATERIALS AND METHODS: A national survey was conducted based on a questionnaire and capillary blood sample taken on filter paper in order to study antibodies against measles, rubella and hepatitis B in children from 1 to 4 years of age. A stratified, multistage, probability sampling design was used to be representative at the national level and at level of seven ambits, including the Metropolitan Lima Area, the rest of the urban coast, the rural coast, the urban highlands, the rural highlands, the urban jungle and the rural jungle. The capillary blood samples were processed according to the standardized protocols for detection of antibodies using the ELISA technique and commercial reagents. RESULTS: The survey showed a national prevalence of antibodies against measles, rubella and hepatitis B of 91.6% (CI 95%: 90.6%; 92.7%), 91.3% (CI 95%: 90.3%; 92.4%) and 95.9% (CI 95%: 95.0%; 96.8%) respectively. There was no evidence of significant differences in the prevalence among the ambits of study or among the socioeconomic strata of the conglomerates for any of the three types of antibodies. CONCLUSIONS: In children from 1 to 4 years of age, the national prevalence of antibodies against measles and Rubella was between 90-93%, while the prevalence of antibodies against Hepatitis B (anti-HBsAg) was between 95-97%.

Haiti 2007-2008 national measles-rubella vaccination campaign: implications for rubella elimination.

BACKGROUND: A national campaign was conducted in Haiti in 2007-2008 to vaccinate all children and adolescents aged 1-19 years with measles-rubella vaccine in support of achieving the Region of the Americas' 2010 goal of eliminating rubella and congenital rubella syndrome (CRS). Measles-rubella vaccine was introduced into the country's routine childhood immunization schedule after the campaign. METHODS: A nationwide, stratified, multistage cluster sample survey of 20859 children was conducted to assess coverage using house-to-house interviews. RESULTS: Estimated national coverage with measles-rubella vaccine was 79.2% (95% confidence interval, 77.6%-80.7%), ranging from 90.2% in Nord-Ouest Department to 70.0% in Cite Soleil Metropolitan Area. National coverage was lower for children aged 1-5 years (76.7%) than for those aged 6-19 years (80.3%) (P< .001) but similar in rural departments (79.4%) and metropolitan areas (78.6%; P = .61). The reasons most frequently cited for nonparticipation in the campaign were that the child was ill or unavailable (18.6%), did not know vaccinations were important (13.8%), did not know when to go or forgot to go (13.3%), and did not have enough time (12.3%). CONCLUSIONS: The measles-rubella vaccination campaign was critical for raising rubella immunity levels in children and adolescents in Haiti. To remain free of rubella transmission and CRS, Haiti must also achieve and sustain high routine measles-rubella vaccination coverage and maintain high-quality integrated measles-rubella and CRS surveillance, including laboratory-based confirmation for reported rash illnesses. If routine measles-rubella vaccination coverage is suboptimal or if gaps in coverage are identified, additional mass campaigns with measles-rubella vaccine will be necessary.

Measles elimination in the Americas: a comparison between countries with a one-dose and two-dose routine vaccination schedule.

BACKGROUND: The Region of the Americas eliminated measles in 2002 through high first-dose routine measles vaccine coverage and vaccination campaigns every 4-6 years; a second routine dose at school entry was added in some countries. The impact of this second routine dose on measles elimination was evaluated. METHODS: Data on socioeconomic factors, demographic characteristics, vaccination coverage, and the estimated proportion of children (<15 years of age) susceptible to measles were compiled. Countries were grouped using propensity score methods, and Kaplan-Meier curves were used to compare time to measles elimination between countries with a 1-dose schedule and those with a 2-dose schedule. RESULTS: One-dose (n = 14) and 2-dose (n = 7) countries did not differ with respect to median routine first-dose measles vaccine coverage, median coverage for 3 measles campaigns, or estimated percentage of susceptible children after routine first vaccination dose and campaigns. Compared with 1-dose countries, 2-dose countries had higher median gross national income per capita (P = .002), percentage of population living in urban areas (P = .04), and female literacy (P = .01), as well as lower infant mortality (P = .007); however, no differences in time to elimination were found. CONCLUSIONS: One-dose and 2-dose countries had similar times to measles elimination despite socioeconomic differences between their populations. A second routine dose might not have hastened measles elimination, because threshold immunity needed to eliminate measles was achieved with high first routine dose coverage and vaccination campaigns. Further research will be needed to determine the applicability of these findings to other regions.

Increasing the time of exposure to aerosol measles vaccine elicits an immune response equivalent to that seen in 9-month-old Mexican children given the same dose subcutaneously.

BACKGROUND: A 30-second aerosol measles vaccination successfully primes children 12 months of age and older but is poorly immunogenic when given to 9-month-old children. We examined the immune responses when increasing the duration to aerosol exposure in 9-month-olds. METHODS: One hundred and thirteen healthy 9-month-old children from Mexico City were enrolled; 58 received aerosol EZ measles vaccine for 2.5 minutes and 55 subcutaneously. Measles-specific neutralizing antibodies and cellular responses were measured before and at 3 and 6 months postimmunization. RESULTS: Adaptive immunity was induced in 97% after aerosol and 98% after subcutaneous administration. Seroconversion rates and GMCs were 95% and 373 mIU/mL (95% confidence interval [CI], 441-843) following aerosol vaccination and 91% and 306 mIU/mL (95% CI, 367-597) after subcutaneous administration at 3 months. The percentage of children with a measles-specific stimulation index ≥3 was 45% and 60% in the aerosol versus 55% and 59% in the subcutaneous group at 3 and 6 months, respectively. CD8 memory cell frequencies were higher in the aerosol group at 3 months compared with the subcutaneous group. Adverse reactions were comparable in both groups. CONCLUSIONS: Increasing exposure time to aerosol measles vaccine elicits immune responses that are comparable to those seen when an equivalent dose is administered by the subcutaneous route in 9-month-old infants.

Vaccine antibodies and T- and B-cell interaction in juvenile systemic lupus erythematosus.

Both systemic lupus erythematosus (SLE) and its treatment can cause immunosuppression and a decreased response to vaccination. We evaluated 30 children and adolescents with SLE, and 14 age-matched healthy subjects (control group) regarding immunophenotyping and lymphocyte apoptosis by flow cytometry, while measles and tetanus antibodies were measured by enzyme-linked immunosorbent assay (ELISA). The SLE group was divided according to disease activity into inactive SLE and active SLE. Individuals with active SLE had lower CD4+ T and natural killer (NK) cells/mm(3) than the control group. Active and inactive SLE individuals had more CD38 molecules/CD8+ T cells and more CD4+ T, CD8+ T and B cells in apoptosis (as assessed by caspase-3 expression) than the control group. Patients with active SLE had a diminished CD28 expression on both CD4+ T and on CD8+ T cells and a higher CD86 expression on B cells than the control group. Measles antibody levels in the SLE groups were similar to the control group. In contrast, tetanus antibody levels were lower in the SLE groups than in the control group. The latter also directly correlated with the CD4+ T-cell and NK-cell counts from SLE patients (regression coefficient, 2.686 and 1.782; p = 0.010 and p = 0.039, respectively). We concluded that despite being up-to-date for tetanus vaccine, SLE patients presented with a poor immune response to tetanus vaccine.

Investigation of measles IgM-seropositive cases of febrile rash illnesses in the absence of documented measles virus transmission, State of São Paulo, Brazil, 2000-2004.

INTRODUCTION: To review measles IgM-positive cases of febrile rash illnesses in the State of São Paulo, Brazil, over the five-year period following interruption of measles virus transmission. METHODS: We reviewed 463 measles IgM-positive cases of febrile rash illness in the State of São Paulo, from 2000 to 2004. Individuals vaccinated against measles < or = 56 days prior to specimen collection were considered to be exposed to the vaccine. Serum from the acute and convalescent phases was tested for evidence of measles, rubella, parvovirus B19 and human herpes virus-6 infection. In the absence of seroconversion to measles immunoglobulin-G, measles IgM-positive cases were considered false positives in individuals with evidence of other viral infections. RESULTS: Among the 463 individuals with febrile rash illness who tested positive for measles IgM antibodies during the period, 297 (64%) were classified as exposed to the vaccine. Among the 166 cases that were not exposed to the vaccine, 109 (66%) were considered false positives based on the absence of seroconversion, among which 21 (13%) had evidence of rubella virus infection, 49 (30%) parvovirus B19 and 28 (17%) human herpes virus-6 infection. CONCLUSIONS: Following the interruption of measles virus transmission, thorough investigation of measles IgM-positive cases is required, especially among cases not exposed to the vaccine. Laboratory testing for etiologies of febrile rash illness aids interpretation of these cases.

Investigation of measles IgM-seropositive cases of febrile rash illnesses in the absence of documented measles virus transmission, State of São Paulo, Brazil, 2000-2004 / Investigação dos casos de doenças febris exantemáticas com IgM reagente contra o sarampo na ausência de transmissão documentada do vírus do sarampo, Estado de São Paulo, 2000-2004

INTRODUCTION: To review measles IgM-positive cases of febrile rash illnesses in the State of São Paulo, Brazil, over the five-year period following interruption of measles virus transmission. METHODS: We reviewed 463 measles IgM-positive cases of febrile rash illness in the State of São Paulo, from 2000 to 2004. Individuals vaccinated against measles < 56 days prior to specimen collection were considered to be exposed to the vaccine. Serum from the acute and convalescent phases was tested for evidence of measles, rubella, parvovirus B19 and human herpes virus-6 infection. In the absence of seroconversion to measles immunoglobulin-G, measles IgM-positive cases were considered false positives in individuals with evidence of other viral infections. RESULTS: Among the 463 individuals with febrile rash illness who tested positive for measles IgM antibodies during the period, 297 (64 percent) were classified as exposed to the vaccine. Among the 166 cases that were not exposed to the vaccine, 109 (66 percent) were considered false positives based on the absence of seroconversion, among which 21 (13 percent) had evidence of rubella virus infection, 49 (30 percent) parvovirus B19 and 28 (17 percent) human herpes virus-6 infection. CONCLUSIONS: Following the interruption of measles virus transmission, thorough investigation of measles IgM-positive cases is required, especially among cases not exposed to the vaccine. Laboratory testing for etiologies of febrile rash illness aids interpretation of these cases.

INTRODUÇÃO: Revisar os casos de doenças febris exantemáticas com IgM reagente contra o sarampo, no Estado de São Paulo, Brasil, durante os cinco anos seguidos a interrupção da transmissão do vírus do sarampo. MÉTODOS: Nós revisamos 463 casos de doenças febris exantemáticas com IgM reagente contra o sarampo, no Estado de São Paulo, Brasil, de 2000 a 2004. Indivíduos vacinados contra o sarampo 56 dias antes da coleta de amostra foram considerados expostos à vacina. Soros da fase aguda e de convalescença foram testados para a evidência de infecção de sarampo, rubéola, parvovírus B19 e herpes vírus 6. Na ausência de soroconversão para imunoglobulina G contra o sarampo, casos com IgM reagente contra o sarampo foram considerados falsos positivos em pessoas com evidência de outras infecções virais. RESULTADOS: Entre as 463 pessoas com doenças febris exantemáticas que testaram positivo para anticorpos IgM contra o sarampo durante o período, 297 (64 por cento) pessoas foram classificadas como expostas à vacina. Entre os 166 casos não expostos à vacina, 109 (66 por cento) foram considerados falsos positivos baseado na ausência de soroconversão, dos quais 21 (13 por cento) tiveram evidência de infecção por vírus da rubéola, 49 (30 por cento) parvovírus B19 e 28 (17 por cento) infecção por herpes vírus humano 6. CONCLUSÕES: Após a interrupção da transmissão do vírus do sarampo é necessária exaustiva investigação dos casos com IgM reagente contra o sarampo, especialmente dos casos não expostos à vacina. Testes laboratoriais para etiologias das doenças febris exantemáticas ajudam na interpretação destes casos.

Humoral and cellular immune responses to measles and tetanus: the importance of elapsed time since last exposure and the nature of the antigen.

OBJECTIVE: This study aims to assess the cellular and humoral immune response pre- and post-vaccine rechallenge in healthy adults with previous exposure to measles (virus or vaccine) and different time intervals since last tetanus vaccine. METHODS: Humoral immunity was tested by ELISA, and cellular immunity was tested by intracellular interferon gamma detection after in vitro stimulation with antigens. RESULTS: While cellular immunity was comparable among vaccinated individuals and those who had measles, higher antibody levels were found in those who had the disease in the past. Both antibodies and CD4(+) T cell tetanus immune responses depended on elapsed time since last immunization. Following a vaccine booster, an increase in cellular immunity and antibodies was observed to both tetanus and measles. Measles humoral response was much more intense among individuals previously exposed to a wild virus. CONCLUSIONS: In an era when natural boosters are less frequent, an immune surveillance might be necessary to investigate waning immunity as occurs for tetanus.

HHV-6 IgG4 isotype response following measles infection.

Human herpesvirus 6 (HHV-6) is widespread in the human population by infecting most individuals in early childhood. After primary infection, HHV-6 establishes a latent infection by remaining in circulating mononuclear cells of healthy individuals. The HHV-6 antibody titer increases after primary infection with measles virus. The present study was undertaken to determine the specific antiviral IgG1, IgG2, IgG3, and IgG4 subclass response patterns to HHV-6 in HHV-6-seropositive individuals with natural measles virus infection, measles vaccination, and rubella virus infection. The purpose of this study was to examine HHV-6-specific IgG isotype response in patients with acute virus coinfection. Serum samples were obtained from individuals who were seropositive for HHV-6 after natural primary infection with measles virus during an outbreak, measles vaccination, or rubella virus infection, and from healthy individuals. Sera were examined by indirect immunofluorescence assays for detection of HHV-6-specific IgG1, IgG2, IgG3, and IgG4 antibodies. A high percentage (69%) of those infected with measles virus had an HHV-6 IgG1 and IgG4 response (P < 0.001, chi(2) test), whereas persons vaccinated against measles, those infected with rubella, and healthy individuals showed an HHV-6 IgG1 response. These results demonstrate that natural measles virus infection induces an HHV-6 IgG isotype response, which suggests a shift in immune activity from a Th1 to a Th2 response. J. Med. Virol. 82:396-399, 2010. (c) 2010 Wiley-Liss, Inc.

A link between the North Atlantic Oscillation and measles dynamics during the vaccination period in England and Wales.

Ecologists have become aware of the role played by interannual climatic variability on the temporal dynamics of infectious diseases. In this report, I present evidence from data on measles cases in England and Wales showing that during the post-vaccination period, the interannual variability of winter weather (represented by the North Atlantic Oscillation, NAO) influences the annual dynamics of the disease. Using annual measles data from seven cities and simple logistic models, this study reveals how, after vaccination, NAO increases its effects on measles fluctuations. In addition, this study shows that vaccination may be represented as a simple vertical and lateral perturbation effect (Royama's classification), by reducing the maximum per capita growth rate and the equilibrium number of infected individuals. The results suggest that vaccination will not lead to outbreaks of measles from regular cyclic to irregular chaotic dynamics. In contrast, because of the reduction in per capita growth rates, the disease dynamics appear to be more stable than during the pre-vaccination period. The analysis of annual data on infectious diseases may be useful for detecting long-term effects of climate and complements the classical analyses and modeling based on monthly or seasonal time-step data.

Sarampión, Rubéola y SRC: Rubella Watch: Compendio de artículos sobre sarampión(1) / Measles, Rubella and SRC: Rubella Watch: Articles compendium on measles (1)

La publicación busca documentar la experiencia regional, pero sobretodo comunicar a los países y a otras regiones del mundo las lecciones aprendidas, así como las experiencias y mejores prácticas derivadas de la iniciativa de eliminación de enfermedades prevenibles por vacunación. Durante los 15 años de este proceso se ha acumulado conocimiento sobre lo que debe hacerse para llevar adelante estas iniciativas y lograr la meta de eliminación.