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 33J.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, 2002Measles 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, 2002Measles 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.
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