Interruption of measles transmission in Brazil, 2000-2001

Neutralizing antibody titers against D8 genotype and persistence of measles humoral and cell-mediated immunity eight years after the first dose of measles, mumps, and rubella vaccine in Brazilian children

OBJECTIVE

Assess the level of measles vaccine-induced neutralizing antibodies against the D8 genotype and the persistence of humoral and cell-mediated immunity in children who received their first dose of the measles, mumps, and rubella vaccine eight years previously.

METHODS

Measles-specific IgG and neutralizing antibodies were determined in serum using ELISA and plaque reduction neutralization test, respectively. Cellular response was evaluated from peripheral blood mononuclear cells (PBMC). IFN-γ-secreting cells, memory B and T cells, and immunological mediators were assayed by ELISpot, flow cytometry, and multiplex liquid microarray assay, respectively.

RESULTS

Antibody concentrations declined over time; however, the vaccine-induced neutralizing antibodies' effect against D8 and vaccinal genotypes persisted. PBMC stimulated with the vaccine virus exhibited specific IFN- γ-measles-secreting responses in most participants. Participants with high levels of neutralizing antibodies showed a higher proportion of activated B cells compared to participants with low levels of neutralizing antibodies, while proportions of memory CD4+ and CD8+ T cells were similar between these groups. PBMC supernatant cytokine levels showed a significant difference between stimulated and non-stimulated conditions for IL-2, TNF-α, IL-10, and CXCL10.

CONCLUSION

Despite the decline in antibody concentrations over time, the participants still demonstrated neutralizing capacity against the measles D8 genotype five to eight years after the second dose of the measles, mumps, and rubella vaccine. Additionally, most of the enrolled children exhibited cell-mediated immunity responses to measles virus stimulation.

Measles, mumps and rubella vaccine 12 months after hematopoietic stem cell transplantation

The measles, mumps and rubella (MMR) vaccine is usually recommended from 24 months after a hematopoietic stem cell transplant (HSCT). Some authors have demonstrated that the MMR vaccination can be safe from 12 months post-HSCT in non-immunosuppressed patients, as recommended by the Brazilian National Immunization Program/Ministry of Health, since 2006. The objectives of this study were to evaluate when patients received MMR vaccine after an HSCT in our care service and if there were reports of any side effects. We retrospectively reviewed the records of HSCT recipients who received at least one MMR dose in our care service, a quaternary teaching hospital in Sao Paulo city, Brazil, from 2017 to 2021. We identified 82 patients: 75.6% (90.1% in the autologous group and 45.1% in the allogeneic group) were vaccinated before 23 months post-transplantation. None reported side effects following the vaccination. Our data support that the MMR vaccination is safe from 12 to 23 months after HSCT.

Assessing the Effects of Measles Virus Infections on Childhood Infectious Disease Mortality in Brazil

BACKGROUND

Measles virus infection induces acute immunosuppression for weeks following infection, and also impairs preexisting immunological memory, resulting in "immune amnesia" that can last for years. Both mechanisms predispose the host to severe outcomes of subsequent infections. Therefore, measles dynamics could potentially affect the epidemiology of other infectious diseases.

METHODS

To examine this hypothesis, we analyzed the annual mortality rates of children aged 1-9 years in Brazil from 1980 to 1995. We calculated the correlation between nonmeasles infectious disease mortality rates and measles mortality rates using linear and negative-binomial models, with 3 methods to control the confounding effects of time. We also estimated the duration of measles-induced immunomodulation.

RESULTS

The mortality rates of nonmeasles infectious diseases and measles virus infection were highly correlated. This positive correlation remained significant after removing the time trends. We found no evidence of long-term measles immunomodulation beyond 1 year.

CONCLUSIONS

These results support that measles virus infection could increase the mortality of other infectious diseases. The short lag identified for measles effects (<1 year) implies that acute immunosuppression was potentially driving this effect in Brazil. Overall, our study indicates disproportionate contributions of measles to childhood infectious disease mortality, highlighting the importance of measles vaccination.

Anti-Covid vaccines: a look from the Collective Health

The paper discusses the complex nature of the pandemic by highlighting the various intrinsic and extrinsic dimensions in the development of SARS-CoV-2 vaccines, with an emphasis on the two most advanced products in clinical testing, namely, the vaccine developed by the University of Oxford associated with the British pharmaceutical company AstraZeneca, and the one developed by Chinese company Sinovac. This choice also stems from the fact that both have testing activities, which, if successful, will lead to future production in Brazil, by Bio-Manguinhos/Fiocruz, Rio de Janeiro, and the Butantã Institute, in São Paulo, respectively. From a conceptual viewpoint, this paper builds on the reflection from the field of Collective Health that addresses the boundaries between the biological and the social spheres. It also seeks to show that, if successful and while important tools for coping with the pandemic, vaccines will not dispense with the continuity of other non-pharmacological measures already used.

Measles outbreak response decision-making under uncertainty: a retrospective analysis

Resurgent outbreaks of vaccine-preventable diseases that have previously been controlled or eliminated have been observed in many settings. Reactive vaccination campaigns may successfully control outbreaks but must necessarily be implemented in the face of considerable uncertainty. Real-time surveillance may provide critical information about at-risk population and optimal vaccination targets, but may itself be limited by the specificity of disease confirmation. We propose an integrated modelling approach that synthesizes historical demographic and vaccination data with real-time outbreak surveillance via a dynamic transmission model and an age-specific disease confirmation model. We apply this framework to data from the 1996-1997 measles outbreak in São Paulo, Brazil. To simulate the information available to decision-makers, we truncated the surveillance data to what would have been available at 1 or 2 months prior to the realized interventions. We use the model, fitted to real-time observations, to evaluate the likelihood that candidate age-targeted interventions could control the outbreak. Using only data available prior to the interventions, we estimate that a significant excess of susceptible adults would prevent child-targeted campaigns from controlling the outbreak and that failing to account for age-specific confirmation rates would underestimate the importance of adult-targeted vaccination.

Waning of measles maternal antibody in infants in measles elimination settings - A systematic literature review

INTRODUCTION

Most infants are born with immunity to measles through maternal antibodies transferred in pregnancy, which decay over time. However, in measles elimination settings, where measles does not circulate endemically and most immunity is from immunization rather than infection, maternal antibody levels are lower. This results in infant immunity that wanes earlier, and a wider susceptibility gap between maternal antibody decay and infant immunization than in non-eliminated settings. We aimed to systematically quantify the extent and duration of protection from measles in infants in settings that have sustained measles elimination.

METHODS

We conducted a systematic review of studies of measles maternal antibody waning in infants in measles elimination settings. We searched MEDLINE, Embase, CINAHL, Scopus, BIOSIS Previews, and Global Health databases for relevant studies. Studies were included if they were set in countries that had eliminated measles for ≥3 years, and if the study cohort included healthy, full-term, unvaccinated infants ≤12 months, born to healthy mothers, and reported a relevant measure of measles maternal antibody in infants. We assessed study quality using the MetaQAT tool.

RESULTS

We identified 4692 unique citations, eight of which met inclusion criteria. One study reported anti-measles antibody in cord blood, six reported antibody in infant sera, and one reported both. Two studies reported that 80 and 100% of infants were protected from measles at birth. One study reported no protection amongst 3-7 month old infants, and another reported limited protection in infants >4 months. The remaining studies reported the proportion of infants with detected antibody, but not the proportion immune.

CONCLUSION

Although limited, these data suggest that in settings that have sustained measles elimination, some infants are susceptible to measles well before the age of routine measles immunization. Setting-specific seroprevalence and vaccine effectiveness studies are required to evaluate this in different jurisdictions.

Optimal vaccine schedules to maintain measles elimination with a two-dose routine policy

Measles was eliminated in the Americas in 2002 by a combination of routine immunizations and supplementary immunization activities. Recent outbreaks underscore the importance of reconsidering vaccine policy in order to maintain elimination. We constructed an age-structured dynamical model for the distribution of immunity in a population with routine immunization and without disease, and analysed the steady state for an idealized age structure and for real age structures of countries in the Americas. We compared the level of immunity maintained by current policy in these countries to the level maintainable by an optimal policy. The optimal age target for the first routine dose of measles vaccine depends on the timing and coverage of both doses. Similarly, the optimal age target for the second dose of measles vaccine depends on the timing and coverage of the first dose. The age targets for the first and second doses of measles vaccine should be adjusted for the post-elimination era, by specifically accounting for current context, including realized coverage of both doses, and altered maternal immunity. Doing so can greatly improve the proportion immune within a population, and therefore the chances of maintaining measles elimination, without changing coverage.

Synthesis of Evidence to Characterize National Measles and Rubella Exposure and Immunization Histories

Population immunity depends on the dynamic levels of immunization coverage that countries achieve over time and any transmission of viruses that occur within the population that induce immunity. In the context of developing a dynamic transmission model for measles and rubella to support analyses of future immunization policy options, we assessed the model inputs required to reproduce past behavior and to provide some confidence about model performance at the national level. We reviewed the data available from the World Health Organization (WHO) and existing measles and rubella literature for evidence of historical reported routine and supplemental immunization activities and reported cases and outbreaks. We constructed model input profiles for 180 WHO member states and three other areas to support disease transmission model development and calibration. The profiles demonstrate the significant variability in immunization strategies used historically by regions and member states and the epidemiological implications of these historical choices. The profiles provide a historical perspective on measles and rubella immunization globally at the national level, and they may help immunization program managers identify existing immunity and/or knowledge gaps.

Investigação de surto de sarampo no Estado do Pará na era da eliminação da doença no Brasil

Resumo Em 27 de julho de 2010, houve a notificação tardia de um resultado de IgM reagente para sarampo em Belém, Pará, Brasil, que gerou uma investigação epidemiológica e medidas de controle e prevenção. Foram encontrados mais dois casos confirmados, irmãos do primeiro caso, com clínica e período de incubação compatível com sarampo. Realizamos busca retrospectiva em hospitais e laboratórios, cujo caso suspeito fora o residente ou visitante do Pará, que entre 1o de maio de 2010 e 4 de agosto de 2010, tenha apresentado febre e exantema acompanhado de tosse e/ou coriza e/ou conjuntivite. Todos os casos identificados foram investigados via contato telefônico e/ou visitas domiciliares. Revisamos 183.854 fichas de atendimento, sendo identificados 56 (0,03%) casos suspeitos. Aplicamos 2.535 doses de vacina tríplice viral distribuídas entre bloqueios e intensificações vacinais. Ocorreu um surto intradomiciliar de sarampo em Belém com detecção e isolamento de genótipo viral importado da Europa. Recomenda-se uma vigilância epidemiológica oportuna e sensível à detecção de casos suspeitos de sarampo e manutenção de coberturas vacinais altas.

Investigation of an outbreak of hypersensitivity-type reactions during the 2004 national measles-mumps-rubella vaccination campaign in Brazil

INTRODUCTION

During Brazil's national measles, mumps, and rubella (MMR) vaccination campaign in August 2004, an unexpectedly high rate of hypersensitivity-type adverse events (HAEs) was reported.

MATERIALS AND METHODS

We reviewed information about children with suspected HAEs reported by clinicians to Brazil's national passive surveillance system for adverse events following immunization (AEFI), compared attack rate of HAE by manufacturer of MMR vaccine used in the campaign, and conducted a case-control study to determine possible risk factors for HAEs.

RESULTS

During the 2004 national campaign, the rate of HAEs following MMR vaccination was one log higher for manufacturer A (15.2/100,000 doses administered) compared to the other two manufacturers (1.2 and 0.6/100,000 doses; p<0.0001); a similar pattern was observed retrospectively in analysis of the 2000-2003 AEFI surveillance (0.95 vs. 0.07 per 100,000 doses administered; p<0.0001). In the case-control study, among the 49 case-patients with HAEs identified, reported symptoms included conjunctival injection (60%), urticaria (55%), fever (54%), and facial edema (53%); no deaths occurred. The median time interval between vaccination and symptom onset was 42min (range: 5min-24h). We did not identify any differences in the proportion of case-patients and control children with a history of known allergy to food (including egg, egg-containing products or gelatin), drugs, or environmental antigens.

DISCUSSION

Our study highlights the importance of a well-functioning routine AEFI surveillance system linked with mass vaccination campaigns. Such a system in Brazil permitted timely detection of HAEs and validation of a safety signal associated with one vaccine manufacturer. Unlike earlier publications, this outbreak linked to a single manufacturer of MMR showed no association with a prior allergic history to eggs or other foods, including gelatin; subsequent studies implicate the dextran stabilizer in MMR from manufacturer A as the likely cause of HAEs.

Historical analysis of birth cohorts not vaccinated against rubella prior to national rubella vaccination campaign, Brazil

BACKGROUND

Brazil conducted mass rubella vaccination campaigns to meet disease elimination goals by 2010. An analysis of rubella vaccination opportunities was conducted to target population groups with concentrations of unvaccinated individuals.

METHODS

Rubella vaccination strategies for all 27 states were reviewed between 1992 and 2006. Yearly vaccination coverage was calculated by dividing number of doses of measles-rubella or measles-mumps-rubella vaccines administered by census estimates of target populations. For annual birth cohorts (1967-2005), percentages of persons not vaccinated prior to 2007 were estimated by subtracting the highest coverage obtained in any vaccination strategy (routine or campaign) from 100%. Cohort analysis results were compared with rubella incidence by population group.

RESULTS

An estimated 28.9 million males and 7.7 million females aged 2-40 years in 2007 remained unvaccinated against rubella, corresponding to 43.0% of males and 11.5% of females of these ages in Brazil. The highest percentages of unvaccinated birth cohorts (93.6%-98.1%) were identified among males aged 26-40 years. In rubella outbreaks reported during 2007, the highest disease incidence (22 cases per 100000 population) occurred among males aged 20-29 years.

CONCLUSIONS

Analysis of rubella vaccination opportunities identified concentrations of unvaccinated adults and adolescents for targeting mass vaccination to eliminate rubella and congenital rubella syndrome in Brazil.

Surveillance of adverse effects following vaccination and safety of immunization programs

The aim of the review was to analyze conceptual and operational aspects of systems for surveillance of adverse events following immunization. Articles available in electronic format were included, published between 1985 and 2009, selected from the PubMed/Medline databases using the key words "adverse events following vaccine surveillance", "post-marketing surveillance", "safety vaccine" and "Phase IV clinical trials". Articles focusing on specific adverse events were excluded. The major aspects underlying the Public Health importance of adverse events following vaccination, the instruments aimed at ensuring vaccine safety, and the purpose, attributes, types, data interpretation issues, limitations, and further challenges in adverse events following immunization were describe, as well as strategies to improve sensitivity. The review was concluded by discussing the challenges to be faced in coming years with respect to ensuring the safety and reliability of vaccination programs.

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.

Achieving measles control: lessons from the 2002-06 measles control strategy for Uganda

BACKGROUND The 2002-06 measles control strategy for Uganda was implemented to strengthen routine immunization, undertake large-scale catch-up and follow-up vaccination campaigns, and to initiate nationwide case-based, laboratory-backed measles surveillance. This study examines the impact of this strategy on the epidemiology of measles in Uganda, and the lessons learnt. METHODS Number of measles cases and routine measles vaccination coverage reported by each district were obtained from the National Health Management Information System reports of 1997 to 2007. The immunization coverage by district in a given year was calculated by dividing the number of children immunized by the projected population in the same age category. Annual measles incidence for each year was derived by dividing the number of cases in a year by the mid-year projected population. Commercial measles IgM enzyme-linked immunoassay kits were used to confirm measles cases. RESULTS Routine measles immunization coverage increased from 64% in 1997 to 90% in 2004, then stabilized around 87%. The 2003 national measles catch-up and 2006 follow-up campaigns reached 100% of children targeted with a measles supplemental dose. Over 80% coverage was also achieved with other child survival interventions. Case-based measles surveillance was rolled out nationwide to provide continuous epidemiological monitoring of measles occurrence. Following a 93% decline in measles incidence and no measles deaths, epidemic resurgence of measles occurred 3 years after a measles campaign targeting a wide age group, but no indigenous measles virus (D(10)) was isolated. Recurrence was delayed in regions where children were offered an early second opportunity for measles vaccination. CONCLUSION The integrated routine and campaign approach to providing a second opportunity for measles vaccination is effective in interrupting indigenous measles transmission and can be used to deliver other child survival interventions. Measles control can be sustained and the inter-epidemic interval lengthened by offering an early second opportunity for measles vaccination through other health delivery strategies.

[Frequency of measles, rubella, dengue and erythema infectiosum among suspected cases of measles and rubella in the State of Pernambuco between 2001 and 2004]

This study had the aim of investigating the frequency of measles, rubella, dengue and erythema infectiosum among suspected cases of measles and/or rubella in the state of Pernambuco, Brazil. A total of 1,161 serum samples collected between 2001 and 2004 were tested for these four viral diseases, using enzyme immunoassays to detect IgM antibodies. Out of this total, 276 (23.8%) samples were positive for one of the four viral diseases analyzed. There were 196 positive cases (16.9%) for dengue, 38 (3.3%) for erythema infectiosum (parvovirus B19), 32 (2.8%) for rubella and 10 (0.9%) for measles. Among the suspected cases of measles and rubella, dengue infection was the most frequent, followed by parvovirus B19. The similarity of the clinical manifestations among rash diseases contributes towards making it difficult to diagnose measles, rubella, dengue and erythema infectiosum on clinical grounds alone. It must be emphasized that the four tests used were insufficient for diagnosing 76.2% of the febrile and rash diseases notified. This is the first study bringing evidence of human parvovirus B19 circulation in Pernambuco.

Elimination of endemic measles transmission in Australia

Elimination of endemic measles transmission is the culmination of a range of control measures at a national level. Current documentation of elimination proposed by WHO's regional offices requires achieving specific targets for surveillance process indicators. We demonstrate how Australia, although not meeting these specific targets, has satisfied multiple criteria that justify the formal declaration of measles elimination. Our review shows that few countries previously declaring measles elimination have satisfied the current WHO surveillance targets. We argue that the requirements for recognition of measles elimination should not restrict countries to a particular type of surveillance system or surveillance criteria.

The unfinished measles immunization agenda

Despite achieving and sustaining global measles vaccination coverage of about 80% over the past decade, worldwide measles remains the fifth leading cause of mortality among children aged <5 years. In May 2002, the United Nations Special Session on Children endorsed the goal of reducing measles deaths by half by 2005. Countries and World Health Organization (WHO) regions that adopted aggressive measles control or elimination strategies have shown excellent results. In 2001, countries in the Americas reported an all time low of 537 confirmed measles cases. Substantial progress in measles control has also been achieved in the WHO Western Pacific Region, in seven southern African countries, and in selected countries in WHO European, Eastern Mediterranean, and Southeast Asian regions. The ongoing measles disease burden and availability of safe and effective measles mortality reduction strategies make a compelling case to complete the unfinished agenda of measles immunization.