Persistence of antibodies induced by measles-mumps-rubella vaccine in children in India

Is it Right Time to Introduce Mumps Vaccine in Indias Universal Immunization Program?

Measles, mumps and rubella are vaccine preventable diseases. However, morbidity and mortality due to these diseases remain largely unnoticed in India. Measles has received much attention; mumps and rubella still need to garner attention. According to the World Health Organization, near-elimination of mumps could be achieved by maintaining high vaccine coverage using a two-dose strategy. However, Government of India has not yet decided on mumps vaccine. In this review, we have reviewed sero-prevalence studies, vaccine studies, outbreak investigations, virus isolation and virus genotyping studies on mumps. Overall, mumps seems to be a significant public health problem in India, but does not garner attention due to the absence of a surveillance and documentation system. Thus, inclusion of mumps antigen in the Universal immunization program would have added advantages, the economic burden imposed by the cost of the vaccine offset by a reduction in disease burden.

Evaluation of Immune Response to Measles Component of MMR Vaccine in Children with HIV Infection Receiving Antiretroviral Therapy

BACKGROUND

Children with HIV (CLHIV) respond poorly to primary immunization with measles vaccine and those responding tend to lose protective titer of antibodies by 2-3 years old. Revaccinating CLHIV after immune reconstitution with antiretroviral therapy (ART) may result in good seroconversion, thereby conferring them protection from measles. The objective was to study prevalence of measles antibodies in CLHIV receiving ART before and after immunization with MMR vaccine.

METHODS

CLHIV in the age 5-18 years receiving ART for >6 months and with CD 4 count >15% were included in this prospective study. Their serum was assayed for IgG measles antibodies by qualitative immune-enzymatic determination using enzyme linked immunosorbent assay. The subjects were then immunized with a single dose of MMR vaccine. A repeat venous sample was assayed for measles antibodies 8-12 weeks after immunization.

RESULTS

Sixty-six subjects (46 males, 20 females, mean age 10.4 ± 2.8 years) were enrolled. The mean duration of ART was 3.4 ± 1.5 years and median CD4 count 716.5 μ/L (interquartile range: 563.3-950). At enrollment, 16 (24.2%) subjects tested positive, 8 (12.1%) equivocal and 42 (63.6%) negative for measles antibodies. After 8-12 weeks of immunization, 62 (93.3%) tested positive, 1 (1.5%) equivocal, and 3 (4.5%) negative. There was no difference among the seropositive and seronegative subjects postimmunization with respect to age, sex, duration of ART, nutritional status, CD4 count, or WHO clinical stage. No serious adverse reaction was observed to vaccination.

CONCLUSIONS

MMR vaccine leads to an excellent seroconversion to measles component of vaccine in immune-reconstituted CLHIV.

Burden of Congenital Rubella Syndrome (CRS) in India: a systematic review

BACKGROUND

Rubella, though a mild, vaccine-preventable disease, can manifest with severe teratogenic effects in the fetus labeled as congenital rubella syndrome (CRS) due to primary maternal rubella infection. Despite a reduction in disease burden of several vaccine-preventable diseases through childhood immunization, CRS continues to account for preventable severe morbidity including childhood blindness, deafness, heart disease, and mental retardation.

OBJECTIVE

To conduct a systematic review to describe the prevalence of CRS and its contribution to major long-term handicaps in Indian population. Another objective was to estimate the susceptibility to rubella infection in Indian adolescent girls and women of reproductive age-group. We also explored strategies to decrease CRS in India by identifying the immunogenicity of rubella containing vaccines (RCV) in Indian children and women, as well as their coverage in India.

METHODS

Publications reporting CRS prevalence in general population as well as selected subgroups i.e., suspected intra-uterine infection, congenital ocular abnormalities, deafness, congenital heart disease, mental retardation, and congenital malformations, seroprevalence to rubella (IgG) amongst women and adolescents, and immunogenicity and coverage of RCVs in Indian population were retrieved through a systematic search. Primary databases employed were Medline through PubMed and IndMed, websites of the WHO, and UNICEF. No restrictions were applied in terms of study designs. The primary outcome measure was congenital rubella syndrome (CRS) which was further categorized as suspected CRS and confirmed CRS as defined by World Health Organization (WHO).

RESULTS

Comprehensive evidence about the true burden of CRS in India is not available. Almost all studies have been done in nstitutional/hospital set-ups and community-based studies are grossly lacking. There are no studies assessing the prevalence of CRS in general population. All studies have evaluated the CRS burden in symptomatic cohorts of children. 1-15% of all infants suspected to have intra-uterine infection were found to have laboratory evidence of CRS. About 3-10% of suspected CRS cases are ultimately proven to have confirmed CRS with the aid of laboratory tests. CRS accounts for 10-15% of pediatric cataract. 10-50% of children with congenital anomalies have laboratory evidence of CRS. 10-30% of adolescent females and 12-30% of women in the reproductive age-group are susceptible to rubella infection in India. RCVs are highly immunogenic in Indian adolescents and women. The coverage data of RCVs in India is not available. However, the coverage of MMR vaccine has been reported as 42%, 30% and 5% from Delhi, Chandigarh and Goa, respectively.

CONCLUSION

This systematic review identifies and explores factors associated with the prevalence of CRS in India. There is a need for urgent action in terms of revamping the national immunization policy and introduction of RCVs in the national immunization program. Active surveillance of rubella and CRS is needed to redress the burden of CRS in India.

Viral Vaccines in India: An Overview

Viruses cause a large number of diseases in humans, some of which are fatal, while others are highly debilitating. A majority of viral diseases attack infants and young children, while others strike people in their prime. Development of preventive measures against viral diseases is, therefore, of paramount importance. Vaccination is the most cost-effective medical intervention for preventing mortality and morbidity against infectious diseases. A number of effective and safe vaccines are currently available against several viral diseases of significant medical importance. Many of these manufactured in India, are at par with international standards and are affordable. For many other viral diseases, for which vaccines are currently not available, research is underway at various national laboratories, as well as in the private sector companies in India. The present overview highlights the various vaccine preventable viral diseases that are of special importance to India and aims to provide a glimpse of the various vaccines that are currently available, or are under development in India.

Persistence and titer changes of rubella virus antibodies in primiparous women who had been vaccinated with strain RA 27/3 in junior high school

Taiwan's rubella vaccination program was launched in 1986; each schoolgirl in the third grade of junior high school received one dose of rubella (RA 27/3) vaccine. We reviewed the results of 14,090 prenatal rubella tests for primiparas from three areas of Taiwan during 2002 to 2008 to investigate seronegativity rates and titer changes. In all primiparous women, the average rubella virus seronegativity rate was 6.5% (95% confidence interval [95% CI], 6.1 to 6.9%), and the average rubella virus antibody titer was 65.9 IU/ml (95% CI, 64.7 to 67.1 IU/ml). There were 1,220 women (8.7%) with weakly positive antibody titers (10 to 20 IU/ml). The rubella virus seronegativity rates, which ranged from 5.4 to 9.7%, did not exhibit a linear trend from 9 to 22 years after vaccination (P = 0.201); in contrast, a significant trend appeared in the average rubella virus IgG titer (P = 0.003), dropping from 69.9 IU/ml in the 9th year after vaccination to 54.8 IU/ml in the 22nd year. The mean annual antibody decay rate was -0.77 IU/ml. This study reveals that the level of rubella virus antibodies declined slowly in women of childbearing age who were vaccinated with RA 27/3 at junior high school age. The number of women who were seronegative or had weakly positive antibody titers was still high (15.2%). Therefore, in countries that implement a single-dose regimen in children or teenagers, it should remain an important policy to encourage voluntary immunization in seronegative women and to immunize all postpartum women who are susceptible to rubella virus infection before they leave the hospital.

Update on available vaccines in India: report of the APPA VU 2010: I

The Asia Pacific Pediatric Association Vaccinology Update 2010 was held in Mumbai on November 13-14, 2010 to discuss the latest information on burden of infectious diseases, recent developments in vaccines and their impact on immunization practices against infectious diseases occurring in Indian children. During the conference the importance of including conjugate Haemophilus influenzae type b vaccine and anti-rabies vaccines in routine immunization was stressed. Also, the need for giving a second dose of measles mumps rubella vaccine at school entry; and the need for a two-dose varicella vaccine regimen (first dose at 12-15 months of age and a second dose at age 4-6 years) was elucidated. Information related to vaccines which have become available in India in recent years, namely, inactivated poliovirus vaccine; diphtheria, tetanus, acellular pertussis (DTaP) vaccine; conjugate pneumococcal vaccine; rotavirus vaccines; H1N1 vaccines; live attenuated hepatitis A virus vaccine; oral cholera vaccine; tetanus, reduced-dose diphtheria, acellular pertussis (Tdap) vaccine; and human papillomavirus vaccines were discussed.