M
easles is a highly infectious and potentially
fatal viral infection mainly affecting children. Immunization against
measles directly contributes to the reduction of under-five child
mortality and hence to the achievement of Millennium Development Goal 4
[1]. Deaths from measles occur mainly in infants and young children and
are primarily due to complications of the infection such as pneumonia
and diarrhea. Measles continues to be a major cause of childhood
morbidity and mortality in India. Although the true burden of measles in
India is difficult to quantify, only a small proportion of cases seek
treatment. Infection with measles virus is ubiquitous throughout the
country.
A recent review of published literature from India
shows the median case fatality ratio (CFR) of measles to be 1.63%
(range: 0%-30.0%) [2]. Malnutrition and young age at infection are risk
factors associated with measles mortality. Recent studies estimate that
80,000 Indian children die each year due to measles and its
complications amounting to 4% of under-5 deaths [3]. The distribution of
these deaths is not homogenous but is concentrated in states with the
poorest performing immunization programs [4-6].
Global Goal for Measles Control
The current global goal for measles control, as
stated in the Global Immunization Vision and Strategy (GIVS) 2006-2015
of the World Health Organization and United Nations Children’s Fund, is
to reduce measles deaths by 90% by 2010 compared to the estimated number
in 2000. World Health Assembly (WHA) has also endorsed the same after
the review by WHO’s Strategic Advisory Group of Experts (SAGE) on
immunization [7].
The key strategies being followed globally for
measles mortality reduction are:
• High coverage of Measles 1
st
dose: Coverage for 1st
dose measles vaccine must be ³90%
at national level and ³80%
for each district in routine immunization.
• Sensitive laboratory supported surveillance:
Outbreak and case based surveillance fully supported by
laboratories for serological and virological classification. An
outbreak is considered confirmed if measles immunoglobulin M (IgM)
is detected in serum from at least two suspected cases.
• Appropriate measles case management:
Including administration of vitamin A to reduce mortality and
complications.
• Providing 2
nd
dose of measles vaccine:
(a) Single dose in routine immunization
- In India, states with
³80%
evaluated coverage for 1st
dose of measles vaccine in Routine Immunization (RI) (DLHS-3) will
have the second dose of measles vaccine in RI with DPT booster [8].
(b) Supplementary immunization activity
(SIA) for measles through catch up immunization campaigns and or
follow up immunization campaigns: States with <80% evaluated
coverage of 1
st dose of
Measles vaccine in RI (DLHS-3) are conducting Measles Catch up
campaigns since 2010 in a phased manner [9].
Measles Vaccines, Effectiveness and Duration of
Protection
Live, attenuated measles vaccines are available,
either as monovalent vaccine or as measles-containing vaccine (MCV) in
combination with rubella or mumps vaccines. When using the combined
measles–rubella vaccine or measles-mumps-rubella vaccine, the protective
immune responses to each individual vaccine antigen as well as
vaccine-associated adverse events remain largely unchanged. Available
measles vaccines are safe, effective and may be used interchangeably
within immunization programs.
Following vaccination, the long-term persistence of
neutralizing measles antibodies (upto 33 years) and long-lasting
protection against measles have been demonstrated. However, it is not
definitively known whether a single dose of measles vaccine, without
natural boosting by recurrent measles exposure, will result in lifelong
protection. Studies using IgG avidity measurements to separate primary
vaccination failures from secondary vaccination failures suggest that
secondary failures may occur occasionally [10,11]. However, declining
immunity has not been shown as an important risk factor [12].
Indications, precautions and contraindications:
Mild illnesses are not a contraindication to vaccination, vaccination
should be avoided if the patient is having high fever or having serious
disease. Measles vaccine can be given to adolescent and adults if
susceptible or travelling to endemic areas but should be avoided during
pregnancy. Early stages of HIV infection is not a contraindication to
measles immunization. People with a history of an anaphylactic reaction
to components of the vaccine should not be vaccinated. Measles vaccine
is also contraindicated in people who are severely immuno-compromised
e.g. severe HIV infection, advanced leukemia or lymphoma, treatment
with high-dose steroids [7].
Where no contraindications have been identified,
measles vaccine should be given to all infants and young children as
part of national immunization programmes. The vaccine may also be
offered to teenagers and adults likely to be susceptible and at risk of
being exposed to measles virus – for example, to those who are
travelling to areas where measles is endemic. The importance of
vaccinating health workers is underlined by the numerous measles
outbreaks occurring in health institutions, affecting both health
workers and patients. Administration of immunoglobulins or other
antibody-containing blood products may neutralize the effect of the
vaccine for 3-11 months, depending on the dose of measles antibody.
Following measles vaccination, receipt of such blood products should be
avoided for 2 weeks if possible [7].
Adverse Reactions: Adverse reactions after
measles vaccination are slight pain and tenderness at injection site and
are transient. About 7 days after vaccination upto 5% children may
experience fever, occasionally inducing febrile seizures (1:3000
children). Transient rash can occur in 2% and thrombocytopenic purpura
in 1:30000 and anaphylactic reactions 1:100,000 following vaccination
[13-15]. Extensive studies in different countries have demonstrated that
there is no increased risk of permanent neurological sequelae and no
evidence to support an increased risk of Guillain-Barré syndrome
following administration of MCVs. There is also no scientific evidence
to support reports that measles vaccination may be a risk factor for
inflammatory bowel disease or for autism [16].
Routine MCV 1 Coverage
In 1985, MCV1 was introduced in India’s Expanded
Program on Immunization, with a recommended age for vaccination of 9-12
months. Estimated national routine MCV1 coverage was 74% among children
aged 12-23 months based on UNICEF sponsored national Coverage Evaluation
Survey (CES) of 2009 [17]; state level MCV1 coverage ranged from 48% to
96%. District level data from the District Level Household and Facility
Survey conducted during 2007-2008 (DLHS-3) indicated that MCV1 coverage
was
£90% in
26% of the evaluated districts [18].
Second Dose of Measles Containing Vaccine (MCV2)
With 70% routine measles vaccination coverage and 85%
vaccine effectiveness with a single dose given at 9 months of age, real
protection to measles is only 60% (0.70 × 0.85=0.60) and thus
approximately 40% of India’s annual birth cohort of 26 million children
remains susceptible to measles. At this rate, the accumulation of
susceptible children in successive annual birth cohorts would reach the
epidemic threshold level every 2-3 years [19].
The rationale for providing a second opportunity for
measles vaccination is two-fold [9]:
• Immunological: To immunize the primary
vaccine failures; those children who failed to respond to the first
dose
• Programmatic: To vaccinate those
children who were missed by routine services for first dose of
measles in routine immunization.
Most children who have failed to respond to the first
dose of MCV respond well to a second dose [7]. MCV2 can be delivered
either through existing routine services or through measles catch-up
immunization campaigns, the choice is determined by the strategy that
would attain the highest levels of coverage.
In weak program settings, organized catch-up
vaccination campaigns that benefit from specific planning and intense
communication and coordination efforts have been proven to effectively
achieve high coverage levels in all socio-economic strata [5,20].
Furthermore, numerous studies from a range of development settings have
found two doses of measles vaccine to be highly cost effective [7]. In
settings of low immunization coverage, the campaign approach has also
been found to be more equitable across wealth quintiles [21].
By 2008, the annual number of measles associated
deaths occurring worldwide had reduced by 78% from 733,000 in 2000 to
164,000 [20]. Sub-Saharan Africa, in particular, has demonstrated the
impact of increasing routine vaccine coverage while also providing a
second opportunity for measles vaccination through measles catch-up
campaigns [22]. From 2000 to 2008, measles deaths in Africa declined by
92%.
NTAGI Recommendations for India
For reducing measles mortality in India, National
Technical Advisory Group on Immunization (NTAGI) reviewed data on
measles epidemiology and case fatality rate and has recommended the
following [23]:
• A second dose of measles vaccine should be
introduced in the UIP at the time of DPT booster dose (at 16-24
months of age) in states with
³80%
evaluated coverage with the first dose of measles vaccine.
• Catch-up measles vaccination campaigns should
be implemented for children aged 9 months to 10 years in states with
<80% evaluated coverage with the first dose of measles vaccine and
that detailed action plans for these SIAs should be finalized
immediately in states with low coverage and high measles mortality
burden.
Indian Academy of Pediatrics endorses NTAGI
recommendations.
India’s Decision to Introduce MCV2
Building on global experience and recognizing that
measles represents a significant source of preventable child mortality,
the Government of India announced in May 2010 its decision to implement
the National Technical Advisory Group on Immunization (NTAGI)
recommendation to introduce MCV2 [4,24]. As recommended by the NTAGI,
the implementation strategy of MCV2 at the state level is determined by
the underlying performance of the routine immunization (RI) program. In
total, 14 states with measles vaccine coverage <80% (Arunachal Pradesh,
Assam, Bihar, Chhattisgarh, Gujarat, Haryana, Jharkhand, Madhya Pradesh,
Manipur, Meghalaya, Nagaland, Rajasthan, Tripura and Uttar Pradesh) will
introduce MCV2 through catch-up vaccination campaigns. In the remaining
21 states with better performing routine immunization systems (i.e.
³80% routine
measles coverage) 17 will introduce MCV2 for children aged 16-24 months
through the routine program. The remaining four States and Union
Territories (Delhi, Goa, Puducherry and Sikkim) already use a second
dose of measles vaccine in their RI program (as mumps-measles-rubella
vaccine) financed with state resources [7]. After the campaigns in the
districts of 14 states, those districts will start the MCV2 in routine
immunization at 16-24 months after 6 months of completing the campaigns.
Supplementary Immunization Activities and Measles
Catch-up Campaigns
Measles catch-up campaigns are indeed SIAs just like
polio SNIDs/NIDs. Supplementary immunization activities are mass
campaigns targeting all children in a defined age group, with the
objective of reaching a high proportion of susceptible individuals. Each
campaign is conducted over a wide geographical area (e.g. province or
country) in order to achieve a rapid reduction in the number of
susceptible children. This is a one-time effort to vaccinate all
children in a defined age group (based on the epidemiology of the
country) irrespective of their prior immunization status (history or
record). The goal is to rapidly reduce the susceptible proportion in a
population and to rapidly enhance population immunity, i.e. the
‘herd immunity’. It is not usual to conduct screening for vaccination
status and prior disease history (i.e. the campaigns are usually
‘non-selective’). Hence anyone who has already received measles vaccine
(or MCV) or has history of measles disease in the past is also
vaccinated [8]. During SIAs, many established principles of vaccination
practices are not adhered to. For example, if a child has received a
dose of measles or MCV just a day before the campaign is also targeted
for a campaign dose. Even being a live vaccine, extra doses of measles
vaccine do no harm, and in fact, may benefit few children with primary
vaccine failure even after booster doses. However, these campaign doses
are not counted and routine vaccination is completed as per the
schedule. The purpose is to rapidly reach a high coverage around 100% in
a short span of time. Furthermore, SIAs also provide an opportunity to
increase community awareness of immunizations and strengthen routine
immunization programs [8].
Challenge for Routine Immunization
Routine vaccination is a critical strategy for
achieving high coverage with MCV1 and MCV2. The government of India is
implementing measures to strengthen routine vaccination, especially in
districts with low coverage. Nevertheless, substantial challenges exist,
including the need for: increasing the number of trained staff at all
levels; increasing public demand for and confidence in vaccines;
improving vaccine stock and cold chain management: and developing a
strong reporting and management system for AEFI [23].
Conflicts of interests: None declared;
Funding: None.
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