Measles: a disease that has to be eradicated

Assessment of using Google Trends for real-time monitoring of infectious disease outbreaks: a measles case study

Measles remains a significant threat to children worldwide despite the availability of effective vaccines. The COVID-19 pandemic exacerbated the situation by leading to the postponement of supplementary measles immunization activities. Along with this postponement, measles surveillance also deteriorated, with the lowest number of submitted specimens in over a decade. In this study, we focus on measles as a challenging case study due to its high vaccination coverage, which leads to smaller outbreaks and potentially weaker signals on Google Trends. Our research aimed to explore the feasibility of using Google Trends for real-time monitoring of infectious disease outbreaks. We evaluated the correlation between Google Trends searches and clinical case data using the Pearson correlation coefficient and Spearman's rank correlation coefficient across 30 European countries and Japan. The results revealed that Google Trends was most suitable for monitoring acute disease outbreaks at the regional level in high-income countries, even when there are only a few weekly cases. For example, from 2017 to 2019, the Pearson correlation coefficient was 0.86 (p-value< 0.05) at the prefecture level for Okinawa, Japan, versus 0.33 (p-value< 0.05) at the national level for Japan. Furthermore, we found that the Pearson correlation coefficient may be more suitable than Spearman's rank correlation coefficient for evaluating the correlations between Google Trends search data and clinical case data. This study highlighted the potential of utilizing Google Trends as a valuable tool for timely public health interventions to respond to infectious disease outbreaks, even in the context of diseases with high vaccine coverage.

Analysis of antibody response by temperature-sensitive measles vaccine strain in the cotton rat model

Measles virus (MeV) vaccine strain, AIK-C, is temperature sensitive (ts), which is thought to be associated with attenuation of virus pathogenicity. In this study, replication and antibody response were examined in cotton rats using viruses carrying different forms of the P gene, which is responsible for the ts phenotype of strain AIK-C and its parental Edmonston strain. When cotton rats were inoculated intranasally, ts viruses neither replicated in lungs, nor reproducibly generated an antibody response. When inoculated intramusculary (i.m.), however, ts strains raised an antibody titer in all animals. This response was not observed when ultraviolet-inactivated virus was used. ts virus, inoculated i.m., was recovered from cotton rat drainage lymph nodes. These results suggest that ts virus, inoculated i.m., could replicate in the cotton rat, presumably at the superficial lymph node, and induce an antibody response. Therefore, cotton rats can serve as a small-animal model for investigating immune responses to safer ts vaccine, as well as recombinant vaccine using AIK-C as a vector for protection against other infectious agents.

Assessment of the health status and risk factors of Kham Tibetan pastoralists in the alpine grasslands of the Tibetan plateau

The health status of Tibetan herders in the Sanjiangyuan region of the Tibetan Plateau, in southwest Qinghai Province, is assessed in this paper. The field study was conducted in 2002 in the context of a broader community development and research framework, the ultimate goal of which is to achieve an effective region-specific programme of preventative health care and training for Tibetan pastoralists. Specifically, the authors analysed the impact of a number of potentially health-related environmental and lifestyle risk factors on self-reported health indicators, with a special emphasis on mother and child health. Several health status indicators were used, including a general morbidity index and a measurement of functional incapacity due to illness in the sample households. Maternal and child health findings were alarming with high rates of miscarriage and infant loss, with no traditional midwives to assist in pregnancy and delivery. Preventable childhood illnesses were also common. Other debilitating diseases included hepatitis, tuberculosis, arthritis (gout), gall bladder disease, peptic ulcers and back pain. Finally, binary logistic regression analysis showed a significant link between general morbidity and the time it takes to obtain water. The survey findings, validated by the focus groups, indicate a real need for increased accessibility and quality of health service provision to women and men and effective preventative health strategies.

The phosphoprotein of attenuated measles AIK-C vaccine strain contributes to its temperature-sensitive phenotype

Measles AIK-C vaccine strain exhibits temperature-sensitivity (ts). To identify the structural proteins, which contribute to the ts property of AIK-C virus, reverse genetics was used. MV-minigenome RNA was replicated at 32.5, 37, and 39 degrees C when the plasmids expressing N, P, and L proteins of the Edmonston strain (the parental strain of AIK-C) were used, whereas the minigenome RNA replicated only at 32.5 degrees C but did not at 37 degrees C and higher temperature when N, P, and L protein expression plasmids of the AIK-C strain were used. A series of minigenome experiments revealed that the amino acid substitution of leucine at position 439 of the P protein by proline (P439-Pro) contributes to the ts phenotype of AIK-C. Four recombinant viruses having various P genes were rescued from the modified AIK-C genome cDNA and ts-characteristics were compared in Vero cells by plaque formation assay. The results showed that the P439-Pro of AIK-C virus played a key role in the ts phenotype, but the other substitutions in the P gene might have an accessory function in the expression of the phenotype.

Measles in Saudi Arabia: from control to elimination

This article describesthe tremendous efforts made in the field of measles immunization in Saudi Arabia in the past 20 years, from the control phase to the elimination phase. Mandatory measles vaccination with one-dose Schwartz vaccine was introduced in 1982 by a royal decree, a step aimed at increasing vaccine coverage. In 1991, a two-dose schedule was implemented using Edmonston-Zagreb measles vaccine, with a first dose at 6 months to protect children younger than 9 months and a second dose of MMR at 12 months of age to protect those who did not respond to the first dose. A marked reduction in the epidemic peak and a shift of infection to older age were noticed. But the same data showed that 50% of measles cases in the 1- to 4-year age group occurred in vaccinated children. In 1998, with the start of elimination phase, an MMR campaign was launched in two phases, targeting school children in 1998 (secondary schools) and in 2000 (primary and intermediate schools). Evaluation of the MMR campaign and surveillance data was reflected in the measles immunization policy by shifting the age of measles immunization to 12 months and to preschool using the two-dose MMR schedule.

The clinical significance of measles: a review

Forty years after effective vaccines were licensed, measles continues to cause death and severe disease in children worldwide. Complications from measles can occur in almost every organ system. Pneumonia, croup, and encephalitis are common causes of death; encephalitis is the most common cause of long-term sequelae. Measles remains a common cause of blindness in developing countries. Complication rates are higher in those <5 and >20 years old, although croup and otitis media are more common in those <2 years old and encephalitis in older children and adults. Complication rates are increased by immune deficiency disorders, malnutrition, vitamin A deficiency, intense exposures to measles, and lack of previous measles vaccination. Case-fatality rates have decreased with improvements in socioeconomic status in many countries but remain high in developing countries.

Measles blindness

Measles remains a major problem in developing countries, where it affects an estimated 30 million children a year and causes up to one million deaths annually. Measles blindness is the single leading cause of blindness among children in low income countries, accounting for an estimated 15,000 to 60,000 cases of blindness per year. There is a close synergism between measles and vitamin A deficiency that can result in xerophthalmia, with corneal ulceration, keratomalacia, and subsequent corneal scarring or phthisis bulbi. High-dose oral vitamin A supplementation is recommended for all children with measles in developing countries. Higher measles immunization coverage to interrupt measles transmission and interventions aimed at improving vitamin A nutriture of children are the main strategies to prevent measles blindness.

Vaccines as tools for advancing more than public health: perspectives of a former director of the National Vaccine Program office

With application of new technologies and licensing of new vaccines, vaccines will soon be better by several orders of magnitude. Yet barriers impede the introduction and wide use of new vaccines. Most of the diseases for which we will have vaccines in the future have not evoked enthusiasm from public health professionals, but not consumer demand, despite ongoing high rates of disease and death. Furthermore, the public's attention turns from the now rarely occurring vaccine-preventable diseases to reports of fears and confirmed adverse events associated with the same vaccines that so effectively continue to prevent disease. New vaccines will be held to a much higher standard; thus we will need more capacity for disease studies, vaccine trials, and surveillance systems. Vaccines and immunization programs contribute to the societal fabric and are an expression of social responsibility. Vaccine research and implementation programs must have the foundation and capacity to keep pace with evolving scientific and societal realities so that their broad benefits can be fully realized.