Measles Resurgence and Drug Development.
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ABSTRACT:
SUBMITTER: Plemper RK
PROVIDER: S-EPMC7492439 | biostudies-literature | 2020 Apr
REPOSITORIES: biostudies-literature
Publications
Measles caused an estimated minimum of one million fatalities annually before vaccination. Outstanding progress towards controlling the virus has been made since the measles vaccine was introduced, but reduction of measles case-fatalities has stalled at around 100,000 annually for the last decade and a 2019 resurgence in several geographical regions threatens some of these past accomplishments. Whereas measles eradication through vaccination is feasible, a potentially open-ended endgame of elimi ...[more]
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Project description:IntroductionIn seven southern African countries (Botswana, Lesotho, Malawi, Namibia, South Africa, Swaziland and Zimbabwe), following implementation of a measles mortality reduction strategy starting in 1996, the number of annually reported measles cases decreased sharply to less than one per million population during 2006-2008. However, during 2009-2010, large outbreaks occurred in these countries. In 2011, a goal for measles elimination by 2020 was set in the World Health Organization (WHO) African Region (AFR). We reviewed the implementation of the measles control strategy and measles epidemiology during the resurgence in the seven southern African countries.MethodsEstimated coverage with routine measles vaccination, supplemental immunization activities (SIA), annually reported measles cases by country, and measles surveillance and laboratory data were analyzed using descriptive analysis.ResultsIn the seven countries, coverage with the routine first dose of measles-containing vaccine (MCV1) decreased from 80% to 65% during 1996-2004, then increased to 84% in 2011; during 1996-2011, 79,696,523 people were reached with measles vaccination during 45 SIAs. Annually reported measles cases decreased from 61,160 cases to 60 cases and measles incidence decreased to <1 case per million during 1996-2008. During 2009-2010, large outbreaks that included cases among older children and adults were reported in all seven countries, starting in South Africa and Namibia in mid-2009 and in the other five countries by early 2010. The measles virus genotype detected was predominantly genotype B3.ConclusionThe measles resurgence highlighted challenges to achieving measles elimination in AFR by 2020. To achieve this goal, high two-dose measles vaccine coverage by strengthening routine immunization systems and conducting timely SIAs targeting expanded age groups, potentially including young adults, and maintaining outbreak preparedness to rapidly respond to outbreaks will be needed.
| S-EPMC10292670 | biostudies-literature
Project description:ObjectivesRecent years have seen increased cases of measles despite widespread vaccination. We examined the potential drivers behind the resurgence of measles.MethodsWe analyzed the trends in measles incidence and vaccine coverage from 2010 to 2019 across World Health Organization member countries using country-level linear regression models. We computed the Spearman rank correlation coefficient (ρ) between measles incidence and socioeconomic and vaccination-related variables using published data from the World Health Organization member countries to identify the key factors influencing measles incidence.ResultsBetween 2010 and 2019, global measles cases fluctuated, with a notable rise in 2019 (measles cases per million in 2019 was about 140% higher than in 2010), alongside a declining vaccination coverage in many countries (59 of 194 countries). Among 10 socioeconomic factors examined, per-capita national gross income, population literacy, urban residences, and political stability were significantly associated with measles incidence (ρ <0, and P <0.05 for all these variables). These factors likely reflect the quality of public health infrastructure (e.g. access to vaccines), particularly, in low- and middle-income countries. In addition, a stratified analysis suggests vaccine hesitancy likely contributed to measles case increases in high- and upper middle-income countries.ConclusionsThe socioeconomic determinants of measles transmission are interconnected and region-specific. The availability of public health resources and political stability significantly influence measles burdens in low- and middle-income countries, whereas vaccine hesitancy presents a unique challenge to measles elimination in high- and upper middle-income countries.
| S-EPMC11498947 | biostudies-literature
Project description:Measles morbidity and mortality decreased significantly after measles vaccine was introduced into China in 1965. From 1995 to 2004, average annual measles incidence decreased to 5.6 cases per 100,000 population following the establishment of a national two-dose regimen. Molecular characterization of wild-type measles viruses demonstrated that genotype H1 was endemic and widely distributed throughout the country in China during 1995-2004. A total of 124,865 cases and 55 deaths were reported from the National Notifiable Diseases Reporting System (NNDRS) in 2005, which represented a 69.05% increase compared with 2004. Over 16,000 serum samples obtained from 914 measles outbreaks and the measles IgM positive rate was 81%. 213 wild-type measles viruses were isolated from 18 of 31 provinces in China during 2005, and all of the isolates belonged to genotype H1. The ranges of the nucleotide sequence and predicted amino acid sequence homologies of the 213 genotype H1 strains were 93.4%-100% and 90.0%-100%, respectively. H1-associated cases and outbreaks caused the measles resurgence in China in 2005. H1 genotype has the most inner variation within genotype, it could be divided into 2 clusters, and cluster 1 viruses were predominant in China throughout 2005.
| S-EPMC2759936 | biostudies-literature
Project description:The Republic of Serbia is a country with ongoing endemic transmission of measles. The aim of this study is to summarize the main characteristics of the measles resurgence that occurred in Serbia in 2014-2015. The national surveillance data on measles was analysed in relation to the clinical, epidemiological and laboratory data. Between November 2014 and December 2015 a measles resurgence with 420 cases was observed in Serbia. Measles virus was initially introduced by and spread among citizens of Bosnia and Herzegovina with temporary residence in Serbia, before spreading to the resident population. Of the 223 patients with available medical records, 173 (77.6%) were unvaccinated. The overall measles incidence during the outbreak was 5.8/100.000. The highest age-specific incidence rate was recorded in children aged ≤4 years (25.9/100.000), but most cases (67.9%) were ≥20 years old. Hospitalization rate was high (32.9%) and included two cases of encephalitis associated with measles. In total, 42 health-care workers and 22 related cases including hospitalized patients (n = 13) contracted measles. The overall percentage of laboratory confirmed cases was 81.7% (n = 343/420). All measles virus sequences except one (D9) belonged to genotype D8, suggesting interruption of transmission after the previous outbreak in 2010-2011 caused by genotype D4 viruses. The growing number of adult patients as compared to previous epidemics, suggests an urgent need for supplementary immunization activities targeting susceptible health care workers, unvaccinated or incompletely vaccinated adults as well as people without vaccination records. The comprehensive investigation of the 2014/2015 measles resurgence will contribute to decisions about appropriate countermeasures to stop the future measles resurgences in Serbia.
| S-EPMC6797132 | biostudies-literature
Project description:Measles infection is of substantial interest to immunologists due to its paradoxical interaction with the immune system. After the acquisition of the measles infection, secondary infection plays a pivotal role in measles-related deaths. A cross-sectional study conducted between December 2018 and July 2019 is presented here. A total of one hundred children of both genders presented with measles complications were included following WHO criteria. Measles confirmation was done by quantitative determination of anti-measles antibodies (IgM) in patients' sera while patient-related demographic data, vaccination status, and other clinical information were obtained on a separate form. The number of female patients (52%) slightly exceeded the number of males (48%). 43% of patients' parents were illiterate, and half of the patients (50%) were from a poor background. The majority of children (76%) who presented with the complications did not receive a measles vaccine. 56% of children were breastfed while 58% received vitamin A supplements but developed complications. The elevated levels of anti-measles IgM were observed in 77% of cases. In both genders, the major complications were pneumonia, lower respiratory tract infection (LRTI), acute diarrhea, diarrhea and LRTI, pneumonia and diarrhea, otitis media and pneumonia, myocarditis and LRTI, and pneumothorax. The majority of the infected children (n = 48) under 12 months of age had associated complications. It has been observed that the measles virus strikes early age children in the northwestern region of Pakistan, which is an alarming situation and is associated with the aforementioned complications, especially in unvaccinated children. Anti-measles IgM is an important serological parameter for early diagnosis of measles infection.Measles infection is of substantial interest to immunologists due to its paradoxical interaction with the immune system. After the acquisition of the measles infection, secondary infection plays a pivotal role in measles-related deaths. A cross-sectional study conducted between December 2018 and July 2019 is presented here. A total of one hundred children of both genders presented with measles complications were included following WHO criteria. Measles confirmation was done by quantitative determination of anti-measles antibodies (IgM) in patients’ sera while patient-related demographic data, vaccination status, and other clinical information were obtained on a separate form. The number of female patients (52%) slightly exceeded the number of males (48%). 43% of patients’ parents were illiterate, and half of the patients (50%) were from a poor background. The majority of children (76%) who presented with the complications did not receive a measles vaccine. 56% of children were breastfed while 58% received vitamin A supplements but developed complications. The elevated levels of anti-measles IgM were observed in 77% of cases. In both genders, the major complications were pneumonia, lower respiratory tract infection (LRTI), acute diarrhea, diarrhea and LRTI, pneumonia and diarrhea, otitis media and pneumonia, myocarditis and LRTI, and pneumothorax. The majority of the infected children (n = 48) under 12 months of age had associated complications. It has been observed that the measles virus strikes early age children in the northwestern region of Pakistan, which is an alarming situation and is associated with the aforementioned complications, especially in unvaccinated children. Anti-measles IgM is an important serological parameter for early diagnosis of measles infection.
| S-EPMC7324859 | biostudies-literature
Project description:Although WHO recommends mass drug administration (MDA) for malaria elimination, further evidence is required for understanding the obstacles for the optimum implementation of MDA. Just before the long rain in 2016, two rounds of MDA with artemisinin/piperaquine (Artequick) and low-dose primaquine were conducted with a 35-day interval for the entire population of Ngodhe Island (~500 inhabitants) in Lake Victoria, Kenya, which is surrounded by areas with moderate and high transmission. With approximately 90% compliance, Plasmodium prevalence decreased from 3% to 0% by microscopy and from 10% to 2% by PCR. However, prevalence rebounded to 9% by PCR two months after conclusion of MDA. Besides the remained local transmission, parasite importation caused by human movement likely contributed to the resurgence. Analyses of 419 arrivals to Ngodhe between July 2016 and September 2017 revealed Plasmodium prevalence of 4.6% and 16.0% by microscopy and PCR, respectively. Risk factors for infection among arrivals included age (0 to 5 and 11 to 15 years), and travelers from Siaya County, located to the north of Ngodhe Island. Parasite importation caused by human movement is one of major obstacles to sustain malaria elimination, suggesting the importance of cross-regional initiatives together with local vector control.
| S-EPMC6910941 | biostudies-literature
Project description:BackgroundWhile a COVID-19 vaccine protects people from serious illness and death, it remains a concern when and how to lift the high-cost and strict non-pharmaceutical interventions (NPIs). This study examined the joint effect of vaccine coverage and NPIs on the control of local and sporadic resurgence of COVID-19 cases.MethodsBetween July 2021 and January 2022, we collected the large-scale testing information and case number of imported COVID-19 patients from the website of the National Health Commission of China. A compartment model was developed to identify the level of vaccine coverage that would allow safe relaxation of NPIs, and vaccination strategies that can best achieve this level of coverage. We applied Monte Carlo simulation 50 000 times to remove random fluctuation effects and obtain fitted/predicted epidemic curve based on various parameters with 95% confidence interval at each time point.ResultsWe found that a vaccination coverage of 50.4% was needed for the safe relaxation of NPIs, if the vaccine effectiveness was 79.3%. The total number of incidence cases under the key groups firstly strategy was 103 times higher than that of accelerated vaccination strategy. It needed 35 months to fully relax NPIs if the key groups firstly strategy was implemented, and 27 months were needed with the accelerated vaccination strategy. If combined the two strategies, only 8 months are needed to achieve the vaccine coverage threshold for the fully relaxation of NPIs. Sensitivity analyses results shown that the higher the transmission rate of the virus and the lower annual vaccine supply, the more difficult the epidemic could be under control. When the transmission rate increased 25% or the vaccination effectiveness rate decreased 20%, 33 months were needed to reduce the number of total incidence cases below 1000.ConclusionsAs vaccine coverage improves, the NPIs can be gradually relaxed. Until that threshold is reached, however, strict NPIs are still needed to control the epidemic. The more transmissible SARS-CoV-2 variant led to higher resurgence probability, which indicates the importance of accelerated vaccination and achieving the vaccine coverage earlier.
| S-EPMC8959078 | biostudies-literature
Project description:Resurgence is defined as an increase in the frequency of a previously reinforced target response when an alternative source of reinforcement is suspended. Despite an extensive body of research examining factors that affect resurgence, the effects of alternative-reinforcer magnitude have not been examined. Thus, the present experiments aimed to fill this gap in the literature. In Experiment 1, rats pressed levers for single-pellet reinforcers during Phase 1. In Phase 2, target-lever pressing was extinguished, and alternative-lever pressing produced either five-pellet, one-pellet, or no alternative reinforcement. In Phase 3, alternative reinforcement was suspended to test for resurgence. Five-pellet alternative reinforcement produced faster elimination and greater resurgence of target-lever pressing than one-pellet alternative reinforcement. In Experiment 2, effects of decreasing alternative-reinforcer magnitude on resurgence were examined. Rats pressed levers and pulled chains for six-pellet reinforcers during Phases 1 and 2, respectively. In Phase 3, alternative reinforcement was decreased to three pellets for one group, one pellet for a second group, and suspended altogether for a third group. Shifting from six-pellet to one-pellet alternative reinforcement produced as much resurgence as suspending alternative reinforcement altogether, while shifting from six pellets to three pellets did not produce resurgence. These results suggest that alternative-reinforcer magnitude has effects on elimination and resurgence of target behavior that are similar to those of alternative-reinforcer rate. Thus, both suppression of target behavior during alternative reinforcement and resurgence when conditions of alternative reinforcement are altered may be related to variables that affect the value of the alternative-reinforcement source.
| S-EPMC5565204 | biostudies-other
Project description:Resurgence, the recurrence of responding due to a worsening of reinforcement conditions for current behavior, is a prevalent form of treatment relapse. Resurgence as Choice in Context predicts that increasing the duration of exposure to reinforcement for target responding during Phase 1 will increase resurgence magnitude, whereas increasing the duration of exposure to reinforcement for alternative responding and extinction for target responding during Phase 2 will decrease resurgence magnitude. We conducted an experiment evaluating these predictions with human participants recruited through Amazon's Mechanical Turk platform. We varied Phase 1 and Phase 2 durations across 4 experimental groups. Resurgence as Choice in Context successfully predicted the differences in resurgence magnitude across these groups, and fitting the quantitative model to the obtained data yielded an exceptional coefficient of determination. We discuss the implications of these results for using Resurgence as Choice in Context to inform experiments with human participants and the feasibility of using human-operant preparations to evaluate resurgence.
| S-EPMC8908731 | biostudies-literature
Project description:Measles and rubella microarray patches (MR-MAPs) are critical in achieving measles and rubella eradication, a goal highly unlikely to meet with current vaccines presentations. With low commercial incentive to MAP developers, limited and uncertain funding, the need for investment in a novel manufacturing facility, and remaining questions about the source of antigen, product demand, and regulatory pathway, MR-MAPs are unlikely to be prequalified by WHO and ready for use before 2033. This article describes the current progress of MR-MAPs, highlights challenges and opportunities pertinent to MR-MAPs manufacturing, regulatory approval, creating demand, and timelines to licensure. It also describes activities that are being undertaken by multiple partners to incentivise investment in and accelerate the development of MR-MAPs.
| S-EPMC8924450 | biostudies-literature