Measles outbreak in Sri Lanka, 1999-2000

Sporadic cases of adult measles: a research article

BACKGROUND

Measles caused by a paramyxovirus, characterized by fever, malaise, cough, coryza conjunctivitis, a maculopapular rash is known to result in pneumonia, encephalitis and death. Fatal cases of measles in Sri Lanka are rare after implementation of the National Immunization Programme in 1984. Thereafter 0.1% case fatality rate was observed during October 1999-June 2000 which is a very low figure compared to other regional countries. Immunization guidelines were further revised in 2001, 2011 and in 2012 when additional immunization was recommended to age group 4-21 years; who are likely to have inadequate immunization, in order to achieve elimination of Measles by 2020. However, in 2013-2014, 4690 cases were reported and the majority were children less than 1 year of age. The occurrence in adults is hard to retrieve in published epidemiological reports, however had been 38% (out of 1008 patients) in the 3rd quarter of 2013. During this outbreak 73/101 (72%) reported from the North Central Province of Sri Lanka had been more than 12 years of age with 50% being more than 29 years. 14 Sri lankan adult patients [median age 32 years (range 25-48)] who presented sporadically from June 2014 to March 2016, with confirmed measles infection were enrolled retrospectively after informed consent. Details with regards to their clinical presentation, immunization and other relevant areas were collected using an interviewer administered questionnaire or using patient management records.

RESULTS

The patients presented with high fever, headache, severe body aches, sore throat, dry cough, intense tearing, red eyes and posterior cervical lymphadenopathy over 3-5 days duration. Later they developed discrete maculopapular rash helping the diagnosis. They had a variable degree of leucopenia, lymphocytosis, thrombocytopenia and derangements in the liver functions mimicking any other acute febrile illnesses such as dengue, chikungunya, leptospirosis or Zika virus infection.

CONCLUSION

At least a 3-5 day delay in the diagnosis was observed (even after the appearance of the rash in some patients), due to non-awareness of its occurrence, unfamiliarity of measles in adults, non-specific nature of the illness and non-availability of rapid diagnostics, risking transmission to the immune-compromised or non-immune staff or patients. Identification of the source of infection in these sporadic adult cases and their virologic surveillance and molecular epidemiology will be important to interrupt the transmission and to achieve the targeted elimination of measles from Sri Lanka by 2020.

The 2013 measles outbreak in Sri Lanka: experience from a rural district and implications for measles elimination goals

BACKGROUND

Sri Lanka was the first country in the Southeast Asian region to achieve its measles elimination goal in 2011. In 2012, the measles immunization schedule changed from a measles vaccine at 9 months to a measles, mumps and rubella vaccine at 12 months. However in 2013, Sri Lanka reported its worst recent outbreak of measles. This study investigated a part of this outbreak in order to describe its epidemiology.

METHODS

A prospective study was carried out at the university medical unit of the Teaching Hospital, Anuradhapura (THA), the third largest hospital in Sri Lanka, from October 2013 until March 2014. An epidemiological profile of patients was constructed, case confirmation was done on all suspected cases and the basic demographic details of these suspected cases were obtained from the available records.

RESULTS

From January 2013 to March 2014, 101 measles suspects were admitted to the THA. Until June 2013, all suspected cases were aged below 12 months of age. During the study period (15 months), the total number of patients aged below 9 months, 9 to 12 months, 1 to 11 years, 12-29 years and over 29 years were 10 (9.9 %), 11 (10.9 %), 6 (5.9 %), 37 (36.6 %) and 36 (35.6 %), respectively (data missing-1). Out of the 33 patients clinically suspected, 32 tested positive for measles. Common clinical features included: fever (n = 33, 100 %), maculopapular rash (n = 33), conjunctivitis (n = 31), posterior cervical lymphadenopathy (n = 23) and Koplik's spots (n = 8). Features suggestive of pneumonia were observed among 30 (90.9 %) patients and 26 (78.8 %) had diarrhoea. Two patients (6.1 %) who developed severe pneumonia received care at an intensive care unit due to respiratory difficulties. Out of 33 patients, 15 (45.5 %) had prior immunization for measles, two (6.1 %) reported that they never had a measles immunization and 16 (48.5 %) were unsure about their immunization status. Out of those who reported they were previously immunized, 11 (73.3 %) belonged to the age group of 12-2 years.

CONCLUSION

Because the first cases of this outbreak were infants, an increase in susceptible infants due to the change in the vaccine schedule could partly explain the outbreak.

A Mixed Outbreak of Rubeola-Rubella in District Kangra of Northern India

BACKGROUND

On 14(th) September 2006, a local community leader informed us about the sudden increase in number of cases of fever and rash in five villages of district Kangra. We investigated the suspected outbreak to confirm the diagnosis and recommend for prevention and control.

MATERIALS AND METHODS

We defined a case of rubeola as the occurrence of fever with rash in children from 3(rd) September to 13(th) January, 2007. We collected information on age, sex, date of onset, residence, signs, symptoms, vaccination and cold chain status. We described the outbreak by place, time and person characteristics. We conducted a retrospective cohort study to estimate vaccine efficacy (VE). We ascertained the measles immunization status by interviewing the mothers and reviewing immunization cards. We confirmed diagnosis clinically, epidemiologically and serologically.

RESULTS

We identified 60 case patients in five villages (41/60 rubeola and 11/60 confirmed epidemiologically linked unvaccinated rubella). The overall attack rate (AR) was 9%. Sex specific AR was 11% for male. Majorities of cases were >5 years of age. No death/minimal complications have occurred. Of 60 case-patients, 42 (70%) were vaccinated for rubeola. The AR of rubeola among unvaccinated children was 25.8% as compared to AR among vaccinated of 4.5% (relative risk: 5.75%; 95% confidence interval: 3.48-9.51 P < 0.001). We estimated general VE to be 83% while gender based VE for male was 84%. Eight case-patients were confirmed serologically for measles immunoglobin M antibodies, two nasopharyngeal swabs positive by polymerase chain reaction. Rubeola virus was genotyped D4. Only 30% (18/60) of the cases took the treatment from modern system of medicine.

CONCLUSION

A mixed outbreak of rubeola/rubella was confirmed clinically, epidemiologically and serologically. We recommend measles and rubella (MR) vaccination at the age of 18-24 months and aggressive Information, Education and Communication (IEC) activities to modify help seeking behavior of the community, especially in the measles affected areas.

Measles vaccination in humanitarian emergencies: a review of recent practice

BACKGROUND

The health needs of children and adolescents in humanitarian emergencies are critical to the success of relief efforts and reduction in mortality. Measles has been one of the major causes of child deaths in humanitarian emergencies and further contributes to mortality by exacerbating malnutrition and vitamin A deficiency. Here, we review measles vaccination activities in humanitarian emergencies as documented in published literature. Our main interest was to review the available evidence focusing on the target age range for mass vaccination campaigns either in response to a humanitarian emergency or in response to an outbreak of measles in a humanitarian context to determine whether the current guidance required revision based on recent experience.

METHODS

We searched the published literature for articles published from January 1, 1998 to January 1, 2010 reporting on measles in emergencies. As definitions and concepts of emergencies vary and have changed over time, we chose to consider any context where an application for either a Consolidated Appeals Process or a Flash Appeal to the UN Central Emergency Revolving Fund (CERF) occurred during the period examined. We included publications from countries irrespective of their progress in measles control as humanitarian emergencies may occur in any of these contexts and as such, guidance applies irrespective of measles control goals.

RESULTS

Of the few well-documented epidemic descriptions in humanitarian emergencies, the age range of cases is not limited to under 5 year olds. Combining all data, both from preventive and outbreak response interventions, about 59% of cases in reports with sufficient data reviewed here remain in children under 5, 18% in 5-15 and 2% above 15 years. In instances where interventions targeted a reduced age range, several reports concluded that the age range should have been extended to 15 years, given that a significant proportion of cases occurred beyond 5 years of age.

CONCLUSIONS

Measles outbreaks continue to occur in humanitarian emergencies due to low levels of pre-existing population immunity. According to available published information, cases continue to occur in children over age 5. Preventing cases in older age groups may prevent younger children from becoming infected and reduce mortality in both younger and older age groups.

Measles outbreaks in displaced populations: a review of transmission, morbidity and mortality associated factors

BACKGROUND

Measles is a highly contagious infectious disease with a significant public health impact especially among displaced populations due to their characteristic mass population displacement, high population density in camps and low measles vaccination coverage among children. While the fatality rate in stable populations is generally around 2%, evidence shows that it is usually high among populations displaced by disasters. In recent years, refugees and internally displaced persons have been increasing. Our study aims to define the epidemiological characteristics and risk factors associated with measles outbreaks in displaced populations.

METHODS

We reviewed literature in the PubMed database, and selected articles for our analysis that quantitatively described measles outbreaks.

RESULTS

A total of nine articles describing 11 measles outbreak studies were selected. The outbreaks occurred between 1979 and 2005 in Asia and Africa, mostly during post-conflict situations. Seven of eight outbreaks were associated with poor vaccination status (vaccination coverage; 17-57%), while one was predominantly due to one-dose vaccine coverage. The age of cases ranged from 1 month to 39 years. Children aged 6 months to 5 years were the most common target group for vaccination; however, 1622 cases (51.0% of the total cases) were older than 5 years of age. Higher case-fatality rates (>5%) were reported for five outbreaks. Consistent factors associated with measles transmission, morbidity and mortality were vaccination status, living conditions, movements of refugees, nutritional status and effectiveness of control measures including vaccination campaigns, surveillance and security situations in affected zones. No fatalities were reported in two outbreaks during which a combination of active and passive surveillance was employed.

CONCLUSION

Measles patterns have varied over time among populations displaced by natural and man-made disasters. Appropriate risk assessment and surveillance strategies are essential approaches for reducing morbidity and mortality due to measles. Learning from past experiences of measles outbreaks in displaced populations is important for designing future strategies for measles control in such situations.

Two doses of measles vaccine: are some states in India ready for it?

We present the results of two surveys of measles outbreaks near Vellore, which perhaps supports the cause for introduction of a second dose of measles vaccine. Survey one had 590 under 10-year olds. The attack rate was 15.1, 11.7 and 5.7% in the unimmunized, among those vaccinated at 6 months and at 9 months, respectively. The overall vaccine efficacy (VE) was 28% if vaccinated at 6 months and 66% if at 9 months. Second survey had 1702 children and adolescents. There were 59 cases of measles of which 49 were over 5 years of age, the mean age being 8.8 years. The VE was 66% for children up to 6 years and 48.4% for those aged 7-15. The data suggests that measles vaccine is better given at 9 months. The low VE in school age children could be improved by introducing a second dose of measles vaccine.

Two Highly Immunized Hilly Areas versus Double Measles Outbreak Investigations in District Kangra, Himachal Pradesh, India, in 2006

BACKGROUND

We investigated two sequential outbreaks of measles in seven villages of Kangra, to confirm the diagnosis and to formulate recommendations for prevention and control.

METHODS

We defined a case of measles as occurrence of fever with rash in a child aged six months to 17 years during the period 3(rd) September to 23(rd) November 2006. We collected information on age, sex, residence, date of onset, symptoms, signs, treatment taken, traveling history and vaccination status. We described the outbreak by time, place and person. We estimated vaccine coverage and efficacy in the affected villages. We confirmed diagnosis clinically, serologically and through genotyping of the virus.

RESULTS

We identified 69 cases. Overall attack rates ranged between 4.2% and 6%. All case patients were between 6 years to 11 years of age. Age-specific attack rate in double outbreaks ranged in between 1.7% and 21.6%, the highest being in the age range 11-17 years. No deaths or complications were reported. The epidemic curve was suggestive of typical propagated pattern. The first outbreak imported virus after an interschool game competition (relative risk, 6.44%; 95% confidence interval, 3.81-10.91); followed by the second outbreak, in which people exchanged foods in the festival in one infected village of the first outbreak (relative risk, 5.3; 95% confidence interval, 1.90-14.77; P <.001). The calculated immunization coverage (93%) coincided nearly with administrative claims. The vaccine efficacies were estimated to be 85% and 81% in the first and second outbreaks respectively. Eleven of the 16 case patients were tested for measles IgM antibodies, while two nasopharyngeal swabs were positive by polymerase chain reaction (PCR) and are genotyped D4 measles strain. Vitamin A supplementations were only given in four villages.

CONCLUSION

Measles outbreaks were confirmed in high-immunization-coverage areas. We recommended (i) second dose opportunity for measles in Himachal Pradesh and (ii) vitamin A supplementation to all the case patients.

Communicable respiratory threats in the ED: tuberculosis, influenza, SARS, and other aerosolized infections

Respiratory infections are the most common communicable infectious diseases. EDs are the front line for patients with respiratory infections because of their acute nature and because the ED is the principal site of health care for those at highest risk. These diseases include influenza, tuberculosis, and measles, together accounting for 25% of infectious causes of death worldwide. These are emerging and biothreat agents that follow the same route of transmission, such as pneumonic plague. We discuss epidemiology, pathogenesis, diagnosis, and treatment of each agent. Emphasis is on the ED's role as a public health prevention arena, with attention to education and disease prevention, early identification of disease in patients at risk, and reduction of illnesses.

Measles transmission following the tsunami in a population with a high one-dose vaccination coverage, Tamil Nadu, India 2004-2005

BACKGROUND

On 26 December 2004, a tsunami struck the coast of the state of Tamil Nadu, India, where one-dose measles coverage exceeded 95%. On 29 December, supplemental measles immunization activities targeted children 6 to 60 months of age in affected villages. On 30 December, Cuddalore, a tsunami-affected district in Tamil Nadu reported a cluster of measles cases. We investigated this cluster to estimate the magnitude of the problem and to propose recommendations for control.

METHODS

We received notification of WHO-defined measles cases through stimulated passive surveillance. We collected information regarding date of onset, age, sex, vaccination status and residence. We collected samples for IgM antibodies and genotype studies. We modeled the accumulation of susceptible individuals over the time on the basis of vaccination coverage, vaccine efficacy and birth rate.

RESULTS

We identified 101 measles cases and detected IgM antibodies against measles virus in eight of 11 sera. Cases were reported from tsunami-affected (n = 71) and unaffected villages (n = 30) with attack rates of 1.3 and 1.7 per 1000, respectively. 42% of cases in tsunami-affected villages had an onset date within 14 days of the tsunami. The median ages of case-patients in tsunami-affected and un-affected areas were 54 months and 60 months respectively (p = 0.471). 36% of cases from tsunami-affected areas were above 60 months of age. Phylogenetic analyses indicated that the sequences of virus belonged to genotype D8 that circulated in Tamil Nadu.

CONCLUSION

Measles virus circulated in Cuddalore district following the tsunami, although there was no association between the two events. Transmission despite high one-dose vaccination coverage pointed to the limitations of this vaccination strategy. A second opportunity for measles immunization may help reducing measles mortality and morbidity in such areas. Children from 6 month to 14 years of age must be targeted for supplemental immunization during complex emergencies.

Young children non-immunized against measles: characteristics and programmatic implications

AIM

To examine the presenting characteristics, including nutritional status, of young children without measles immunization and to suggest appropriate public health measures to improve immunization status.

METHODS

In this retrospective case-control analysis, we studied 4075 children aged 12-23 mo of either sex, who attended ICDDR,B's Dhaka hospital during 1994-2003. Cases included children who reported to this facility without receiving measles vaccine, and the control children were those who received the vaccine.

RESULTS

3181 of 4075 (78%) children, including 1227 (39%) girls and 1954 (61%) boys, received measles immunization. The proportion of vaccinated children increased from 74% in 1997 to 82% in 2001. Some non-specific effects of measles immunization were observed. Fifty-one per cent of the children without measles immunization were stunted, 76% were underweight, and 48% were wasted. The non-immunized children were twice as likely to be stunted, underweight, and wasted than the immunized children; they were more often dehydrated (some or severe dehydration) (28% vs 22%, p<0.001), required longer duration (>72 h) of hospitalization (15% vs 10%, p<0.001), did not receive vitamin A capsule in the previous 6 mo (56% vs 36%, p<0.001), and had more frequent abnormal lung auscultation indicative of acute lower respiratory tract infections (8% vs 5%, p<0.001). Female children, illiterate mother, lack of vitamin A supplementation, and history of measles were significantly associated with non-immunization against measles after controlling for co-variables. Results were similar when different nutritional indicators (underweight, stunting, or wasting) were added separately to logistic regression models.

CONCLUSION

Intervention strategies to enhance immunization coverage in infants should target illiterate mothers and their children, particularly the females and malnourished ones, provide them with measles immunization and vitamin A capsule, and encourage their periodic follow-up visits as part of a preventive nutritional programme.

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.