Measles Outbreak in a Periurban Area of Chandigarh : Need for Improving Vaccine Coverage and Strengthening Surveillance
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Original Article Measles Outbreak in a Periurban Area of Chandigarh : Need for Improving Vaccine Coverage and Strengthening Surveillance J.S. Thakur,1 R.K. Ratho,3 S.P.S. Bhatia,1 Raminder Grover,3 M. Issaivanan,2 Bashir Ahmed,3 Veena Parmar2 and H.M. Swami1 1 Department of Community Medicine and 2Pediatrics, Govt. Medical College & Hospital 3 Department of Virology, Post Graduate Institute of Medical Education & Research, Chandigarh, India. Abstract : Objective : An outbreak of measles was investigated in the periurban areas of Chandigarh Union Territory, during the months of December 1998 to February 1999. Mainly the children below 15 years of age were affected. The children of migrant labourers belonging to the neighbouring states of Uttar Pradesh and Bihar constituted the majority of population in the area under study. They belonged to lower socio economic status with low immunization coverage. Methods : A total of 2968 houses were surveyed for epidemiological investigations in the areas of colony No. 5, Ramdarbar, Palsora and Pandit colony of Kajheri, covering a population of 14,601 and 7.3% (216/2968) of families were affected in the outbreak. Results : Two hundred and eighty three cases of measles were reported with an attack rate of 4.5% and male to female ratio of (M:F) 5.3%:3.6%. Among the measles cases, 48.8% had received measles vaccination. The outbreak was investigated by detecting measles specific IgG/IgM antibodies either in acute or convalescent serum samples or both. Due to inadequate surveillance system and containment measures, the outbreak was in full swing during the winter months. Measles related complications were reported in 31.1% cases (i.e. diarrhoea in 15.2% and Pneumonia is 7.1%). Conclusion : Following smallpox and guinea worm eradication, WHO’s next thrust, is on eradication of poliomyelitis and measles. Hence, strengthening of disease surveillance as well as vaccination policies are mandatory to achieve disease control in these areas. [Indian J Pediatr 2002; 69 (1) : 33-37] Key words : Disease outbreak; Measles; Immunization; Attack rate. Measles is a global problem with variable incidence. response was initiated on the basis of a report that four Significant progress has been made towards measles cases with post measles complications were admitted in elimination from the Americas till relative resurgence of children ward of Govt. Medical College & Hospital, measles during 1997, although it represented only 0.3% of Chandigarh on 8th December 1998. Based on this, the the total reported global cases. 1 The World Health present study was undertaken to investigate the extent of Assembly in 1998 resolved to reduce measles morbidity the problem, possible factors responsible for its occurrence and mortality by 90% and 95% respectively. By the end of and to institute preventive and control measures. 1997, estimated worldwide measles morbidity and mortality were reduced by 74% and 85% respectively, and MATERIALS AND METHODS by 70% and 88% respectively in South East Asia2. Measles Study Area is a serious childhood disease in India, with a median case fatality ratio (CFR) of 2.5%, which increases considerably The study area consisted of affected periurban slum during the outbreak3. During 1995 and 1996 all States and colonies of Union Territory of Chandigarh namely colony Union Territories of the country except Assam, Bihar, no.5, Ramdarbar Phase-I, Pandit colony of Kajheri and Sikkim, Pondicherry, and Chandigarh reported cases of rural area of Palsora as shown in Fig 1. The total measles with a total of 40,542 and 34,935 respectively for population of the study area was 14,601 residing in 2968 these years as per Central Bureau of Health Intelligence families as shown in Table 1. Majority of the people in the report, Govt. of India.4 Outbreaks of measles are often colonies are migrants and have come from Bihar, Uttar reported from rural and tribal areas.5-11 Pradesh, Rajasthan and other states and work as petty The present study highlights a measles outbreak from labourers. The population characteristics were almost an area that had remained free from disease. Outbreak similar for all areas with close proximity with each other Reprint requests : Dr. J.S. Thakur, Senior Lecturer cum Epidemiolo- spread over a distance of 6-7 kilometers. Environmental gist, Department of Community Medicine, Govt. Medical College, conditions and sanitation was poor in all areas with many Sector 32-A, Chandigarh-160 047, India. Fax : 0172-609360 people going for open defecation despite mobile latrines. E-mail : jsthakur_in@yahoo.co.in. Indian Journal of Pediatrics, Volume 69—January, 2002 33
J.S. Thakur et al Health facilities in colony No. 5, are provided by SCOVA was generalized blotchy rash lasting 3 or more days with dispensary run by Local Lion’s Club with about ten H/o fever and H/o any one of the following : cough, medical practitioners who indulge in quackery, and other running nose, red eye. The second proforma was used for three areas each had Govt. Dispensary or Institution. line listing of measles cases containing patient Reporting from local health facilities was inadequate and characteristic including clinical and outcome details. irregular resulting in poor surveillance of disease. Most of The measles case identified based on history and the measles cases were going unreported, resulting in late clinical examination were subjected to laboratory detection of outbreak. Diagnosis was either not examination based on serology and for this purpose every mentioned or not adequately recorded making 10th child was randomly selected. However, if parents of surveillance difficult. child refused, then next child was selected. Detection of the measles specific IgG and IgM antibodies were carried Investigations out using Micro ELISA kit in randomly selected cases at A cross sectional survey was undertaken to investigate department of Virology, Postgraduate Institute of Medical the extent of problem, possible factors responsible and Education and Research, Chandigarh. relevant data first in colony no. 5 from 8-10th December Containment Measures 1998, followed by other areas. Despite control measures recommended after out break in colony no. 5, three areas Health education regarding measles and measles related namely Ramdarbar, Pandit Colony of Kajheri and Palsora complication i.e. diarrhoea, pneumonia and otitis media were not taken for measles immunization. Measles cases were imparted to the inhabitants of these areas by the were reported from these areas in February 1999 which investigators. ORS packets alongwith their use, were were investigated from 23rd-28th February 1999. As all distributed to diarrhoea cases and cotrimoxazole in 2968 families from four affected slum areas were included suspected pneumonia cases. All measles cases received in the survey, no sampling method was needed. The Vitamin A solution. The medical officers, health personals household survey was carried out by a specially trained from the Director Health Services and District Maternal teams of doctors and MBBS students by using two and Child Health Officer of Chandigarh were well predesigned and pretested proformas. The first proforma appraised of the situation on 9th December 1998. The contained socio demographic data about family, age, sex, preliminary survey reports were dispatched to them. immunization status of children and presence of measles Measles vaccine was administered to each child under 5 case etc. Standard case definition used for a measles case years of age by the local health department. The outbreak 1 2 3 1 PALSORA KAJHERI 2 COLONY-5 3 RAMDARBAR Fig.1. Study Area – Chandigarh, India 34 Indian Journal of Pediatrics, Volume 69—January, 2002
Measles Outbreak in a Periurban Area of Chandigarh reappeared in February 1999 in areas with inadequate and 3.6% in females. The highest attack rate of 8.2% was vaccination. Passive measles surveillance work was observed in 1-5 years age group. Among 283 measles carried out in collaboration with the local dispensary cases, 216 were primary and 67 secondary cases. Of the health personals. The critically ill patients were referred to total cases 77.7% of them occurred above 2 years of age the Government Medical College Hospital, Chandigarh. indicating accumulation of susceptible population in this suburban inhabitation. Indirectly, this reflected the poor RESULTS immunization coverage due to floating and unstable population residing within poor sanitary environment At the time of detection, the outbreak was at its peak and overcrowding which favours the intra and inter activity. The first two cases of measles were suspected familial transmission of measles virus within the during the pulse polio immunization campaign on 6th community. Among the surveyed populations, measles December 1998. It appeared as if many such cases were immunization coverage was 47.7% in 12-23 month old misdiagnosed as upper respiratory tract infections. A children. Immunization status of measles cases is shown house to house survey was done of all four areas covering in Fig. 2. Interestingly 48.8% of measles cases gave history a population of 14,601. A total of 283 cases of measles of immunization. During the survey it was apparent that were reported during the outbreak. The outbreak cases started from the months of July 1998 with peak in emerged in biphasic manner. The beginning spurt was in the month of November 1998 and it reappeared in 10.20% February, 1999. The distribution of measles cases 48.80% 48 immunized alongwith their families are depicted in Table 1. 7.3% of the families in the locality were affected in the outbreak. unimmunized Since population characterization and health facilities unknown % were almost similar in all areas, further analyses were 41.00% done as pooled data. Age and sex specific measles attack rates as well as morbidity are shown in Table 2. An Fig. 2. Immunization Status of Measles Cases in Chandigarh overall attack rate of 4.5% was observed in the affected population with a sex specific attack rate of 5.3% in males TABLE 1. Distribution of Families Affected and Measles Cases in 120 110 Different Areas of Chandigarh 100 Distribution Colony Ram Palsora Pandit All of No. 5 Darbar Colony Areas 80 Families Total 1817 722 326 103 2968 59 Affected 82 79 51 4 216 60 46 50 Percent 4.5 10.9 45.6 3.9 7.3 Polulation Total 8260 4329 1574 438 14604 0-15 years 3634 1878 638 219 6269 40 Measles Cases 107 101* 66 9* 283** Attack Rate 2.9 5.3 10.3 3.7 4.5 15 20 among 0-15 years (%) 1 1 1 0 Jul-98 Aug Sept Oct Nov Dec Jan-99 Feb one case above 15 year was excluded for calculations Two cases above 15 years were excluded for calculations. Fig. 3. Trends of Measles Cases in Chandigarh TABLE 2. Age and Sex Specific Measles Morbidity in Chandigarh Age Group Males Females Total Sub. Cases Attack Sub. Cases Attack Sub. Cases Attack Rate % Rate% Rate%
J.S. Thakur et al TABLE 3. Clinical Characteristics of Measles Cases in Chandigarh cases and single convalescent samples in 17 cases; thus the 1998-99 IgM positivity was 60% and 76.5% respectively in these Sr.No. Characteristics Number Percentage samples. Whereas IgG was detected in 90.9% to 100% (n=283) cases (Table 4). Of the 9 apparently healthy contacts/ controls, only 2 (22.2%) had IgM antibodies and 7 (77.7%) 1. Total Cases 283 100 had IgG antibodies. Male 178 62.9 Female 105 37.1 2. Presenting Symptoms DISCUSSION Fever 283 100 Rash 283 100 Although measles is endemic in India but Chandigarh Cough 213 75.3 had maintained disease free status since 1995. The present Red Eye 201 71.0 Running Nose 177 62.5 study shows changing epidemiology of diseases. 7.8 % Vomiting 2 0.7 cases were below one year of age and about three forth 3. Complications (n=88) 31.1% cases (77.7%) were above two years which is indicative of Diarrhoea 43 15.2 the accumulation of susceptible population. Median age Pneumonia 20 7.1 of the cases was three years, which was comparable to the Otitis Media 4 1.4 Encephalitis 1 0.3 previous outbreaks reported in India.6,8,10 Although mean Diarrhoea +Pneumonia 10 3.6 age of the cases was 4.2 years. Beside this there were two Diarrhoea + Otitis media 4 1.4 cases among adults, one 30 years and other 28 years Diarrhoea + Otitis media + 4 1.4 female which was uncommon in India. It showed that Pneumonia there was a shift in the age group affected towards higher 4. Outcome Not yet recovered 69 24.4 side and below one year. Recovered 213 75.3 Overall attack rate of 4.5% in present study was lower Death 0 0 than as reported by others in the country.5-11 There was no LAMA 1 0.35 death reported despite prevalent malnutrition in the area. Similar finding had also been reported from Sevagram in LAMA-Left against medical advice. Maharashtra State.8 However a median case fatality rate TABLE 4. Results of Micro Elisa to Detect IgM and IgG Antibodies of 2.5% had been reported for India, which increased to Measles Antigen considerably during outbreaks. 3 Measles related complications in 31.5% cases in the present study were Patients IgM Micro ELISA IgG Micro Elisa lower than the other studies available from India7,9. Low No. positive/No No. positive/No tested tested attack rates, no mortality and fewer complications indirectly reflected the mild nature of outbreak. The Paired samples 7/8* (87.5) 9/9 (100) measles vaccine coverage of the area was only 47.7% in (acute-convalescent) 12-23 month age group and was comparable to 50.3% in Single acute sample 15/25 (60.0) 10/11 (90.9) Single convalescent sample 13/17 (76.5) 11/11 (100.0) slums of Chandigarh as per coverage evaluation survey of Control samples 2 /9 (22.2) 7/9 (77.7) routine immunization done in 1997-98 with 70.6% each for DPT and OPV and 92% for BCG. However, overall Figures in Parentheses are Percentages measles vaccine coverage for Chandigarh was 69.6% * One paired sample could not be tested for IgM antibodies - Seroconversion (acute-negative, convalescent become positive) which was less than the national average of 81% for was noted in one case. India. 2 There was a need to strengthen routine - IgM could not detected in one convalescent sample. immunization with measles. The unvaccinated or partially protected human beings serve as the reservoir of the month of November 1998 and February 1999 as measles virus. The immunization coverage among shown in Fig. 3. Clinical characteristics of measles cases apparently healthy children within 2 years of age was are shown in Table 3. Fever and rash were present in all 47.7% only rendering rest of the children susceptible to cases. Measles related complications were present in the infection. Surprisingly 48.8% of the affected measles 31.1% cases with diarrhoea in 15.2% followed by cases gave a history of immunization during childhood pneumonia (7.1%). One case with encephalitis was which indicates an underlying cause of vaccine failure or admitted in local hospital. There was no mortality in this short lasting immune response as was reported by Vitek outbreak. Table 4 reveals the measles specific IgG and CR et al12. Such reports are also available from Quebec13 IgM antibodies by Micro ELISA. Out of the nine acute- and Suburban Houston14. Increased protection during a convalescent paired samples collected from measles cases, measles outbreak was observed in children who were one sample could not be tested for IgM antibodies. The previously vaccinated with a second dose of MMR as has overall measles specific IgM positivitiy was noted in 7/8 been reported from Mesa County in USA. The estimated (87.5%) cases whereas all paired samples were positive for vaccine effectiveness was 92% with one dose and 100% IgG antibodies. We could get only acute samples from 25 following 2 doses.12 The significantly lower attack rate in 36 Indian Journal of Pediatrics, Volume 69—January, 2002
Measles Outbreak in a Periurban Area of Chandigarh this outbreak among children who had received two measles can be linked with surveillance of AFP, which doses of measles vaccine provide evidence that a two dose will be a cost affective approach. As per WHO, linking strategy might achieve a level of immunity sufficient to measles surveillance with AFP surveillance is a key prevent measles in children. This also supports the strategy for accelerating measles control in countries with recommendations of Indian Academy of Pediatrics for effective polio eradication programme.2 second dose with MMR at 15-18 months of age. During 1985 to 1988 persistent school outbreaks in USA Acknowledgements demonstrated that even a completely implemented one Authors are thankful to Dr. Nancy Malla, Professor and Head, dose strategy could fail because of high contact rate in Department of Virology, PGIMER, Chandigarh, staff members schools, and the high contagiousness of measles.15-16 It is Health Department, Union Territory of Chandigarh and staff of the recommended that two dose strategy for measles vaccine Department of the Community Medicine, Govt. Medical College have to be considered to prevent frequent outbreaks in Chandigarh for their cooperation and help. developing countries. REFERENCES As soon as the outbreak was noticed, the public health personnels started vaccinating the susceptible population 1. World Health Organization. Progress towards elimination of measles in the Americans. Weekly Epidemiological Record 1998; in these areas. Hence, the presence of measles specific IgG 73 : 81-88. antibodies may be the outcome of recent/past vaccination 2. World Health Organization. Measles control, WHO South or as a consequence of subclinical exposure in the locality. East Asia Region. Weekly Epidemiological Records 1999; 74 : 209- Since the outbreak appeared to have started from July 216. 1998 onwards giving ample time for subclinical exposure 3. Singh J, Sharma RS, Verghese T. Measles mortality in India: A review of community based studies. J Comm Dis 1994; 26 : 203- thus the presence of IgG antibodies may not be a good 214. indicator of past vaccine failure. The presence of measles 4. Measles, CD Alert, Monthly newsletter on Communicable specific IgM antibodies in apparently healthy controls Diseases, National Institute of Communicable Disease, indicates the recent subclinical infection. During an Directorate General of Health Services, Govt. of India 1997; 1.5 ongoing epidemic, 22.2% subclinical recent infection with : 1-8. 5. Risbud AR, Prasad SR, Mehendale SM et al. Measles outbreak measles virus is compatible with the previous reports of in a tribal population of Thane District, Maharashtra. Indian Prasad et al 17 and Risbud AR et al due to highly Pediatr 1994; 31 : 543-351. contageous nature of measles virus.5 The transmission 6. Sharma RS, Kaushic VK, Johri SP, Ray SN. An epidemiological period of measles is usually in winter and spring in India. investigation of measles outbreak in Alwar, Rajsthan. J Com However in this area it was observed that transmission Dis 1984; 16(4) 299-302. season seems to continue even during summer months. 7. Sharma RS. An epidemiological study of measles epidemic in District Bhilwara, Rajsthan. J Com Dis 1988; 20(4): 301-311. The surveillance of disease was found to be inadequate in 8. Jajoo UN, Chhabra S, Gupta OP, Jain AP. Measles epidemic in the surveyed areas. This was due to inadequate training of a rural community near Sevagram (Vidarbha). Indian J Pub health workers regarding the early recognition of measles Health 1984; 28 : 204-207. cases, as well as inappropriate reporting system. This had 9. Bhatia R. Measles outbreak in village Tophema in Nagaland. resulted in late recognition of the outbreak and J Com Dis 1985; 17 : 185-189. 10. Mathews T, Jadhav M, John TJ. Measles in well nourished consequent delay in instituting containment measures. children. Indian Pediatr 1971; 8 : 68-70. Despite routine measles vaccine coverage of >80% 11. Salunke SR, Natu N. Epidemiological investigations of since 1990 in India, measles is a major cause of morbidity measles outbreak in Ajiwali. Indian Pediatr 1977; 14 : 579-579. and mortality among children aged below five years with 12. Vitek CR, Adudell M, Brinton MJ et al. Increased protection wide interstate variations. Strengthening of routine during a measles outbreak of children previously vaccinated with a second dose of measles-mumps-rubella vaccine. Pediatr vaccination should be the cornerstone of measles control Infect Dis J 1999; 18 : 620-623. to achieve >90% coverage and it could be achieved by 13. Boulianne N, De-Serres G, Duval B et al. Major measles identifying population without access to routine coverage, epidemic in the region of Quebec despite a 99% coverage. Can raising community awareness of the need for vaccination J Pub Health 1991; 82(3) : 189-190. and providing sustainable outreach services. The 14. Maston DO, Byington C, Canfield M, Albrecht P, Feigin RD. introduction of second dose of measles vaccine as Investigation of measles outbreak in a fully vaccinated school population including serum studies before and after recommended by Indian Academic of Pediatrics should be vaccination. Pediatr Infect Dis J 1993; 12(4) : 292-999. considered in National Immunization Schedule of India. 15. Markowitz ZE et al . Patterns of transmission in measles Administration of measles vaccine along with OPV could outbreaks in the United State, 1985-86. N Engl J Med 1989; be organized during National Immunization days (NID) 320 : 75-81. in area with poor coverage as had been done recently in 16. Hutchins SS et al. Measles outbreaks in the United States, 1987 through 1990. Pediatr Infect Dis J 1996; 15 : 31-38. Bangladesh, Philippines, and Vietnam. Strengthening 17. Prasad SR, Shaikh NJ, Verma S, Banerjee K. IgG and IgM measles surveillance is critical to document the changing antibodies against measles virus in unvaccinated infants from epidemiology of measles and to evaluate the impact of Pune; evidence for subclinical infections. Indian J Med Res vaccination activities in the region. Surveillance of 1995; 101 : 1-5. Indian Journal of Pediatrics, Volume 69—January, 2002 37
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