HIV-1 infection as a risk factor for incomplete childhood immunization in Zambia

Using geospatial models to map zero-dose children: factors associated with zero-dose vaccination status before and after a mass measles and rubella vaccination campaign in Southern province, Zambia

INTRODUCTION

Despite gains in global coverage of childhood vaccines, many children remain undervaccinated. Although mass vaccination campaigns are commonly conducted to reach these children their effectiveness is unclear. We evaluated the effectiveness of a mass vaccination campaign in reaching zero-dose children.

METHODS

We conducted a prospective study in 10 health centre catchment areas in Southern province, Zambia in November 2020. About 2 months before a national mass measles and rubella vaccination campaign conducted by the Ministry of Health, we used aerial satellite maps to identify built structures. These structures were visited and diphtheria-tetanus-pertussis (DTP) and measles zero-dose children were identified (children who had not received any DTP or measles-containing vaccines, respectively). After the campaign, households where measles zero-dose children were previously identified were targeted for mop-up vaccination and to assess if these children were vaccinated during the campaign. A Bayesian geospatial model was used to identify factors associated with zero-dose status and measles zero-dose children being reached during the campaign. We also produced fine-scale zero-dose prevalence maps and identified optimal locations for additional vaccination sites.

RESULTS

Before the vaccination campaign, 17.3% of children under 9 months were DTP zero-dose and 4.3% of children 9-60 months were measles zero-dose. Of the 461 measles zero-dose children identified before the vaccination campaign, 338 (73.3%) were vaccinated during the campaign and 118 (25.6%) were reached by a targeted mop-up activity. The presence of other children in the household, younger age, greater travel time to health facilities and living between health facility catchment areas were associated with zero-dose status. Mapping zero-dose prevalence revealed substantial heterogeneity within and between catchment areas. Several potential locations were identified for additional vaccination sites.

CONCLUSION

Fine-scale variation in zero-dose prevalence and the impact of accessibility to healthcare facilities on vaccination coverage were identified. Geospatial modelling can aid targeted vaccination activities.

Gaps in knowledge about the vaccine coverage of immunocompromised children: a scoping review

Immunocompromised children are at increased risk of severe illness from vaccine-preventable infections. However, inadequate vaccine coverage remains a concern. This scoping review sought to determine the current state of knowledge regarding vaccine coverage of immunocompromised children. Bibliographic databases were searched for primary research from any year. Data were analyzed quantitatively and narratively. Ninety-seven studies met inclusion criteria. The most commonly studied vaccines were pneumococcal (n = 46), influenza (n = 44), diphtheria/tetanus/pertussis/poliomyelitis/Haemophilus influenzae type B/hepatitis B-containing (n = 36), and measles- and/or mumps- and/or rubella-containing (n = 29). Immunocompromising conditions studied included cancer/stem cell transplants (n = 24), solid organ transplants (n = 23), sickle cell disease (n = 21), immunosuppressive therapy (n = 14), human immunodeficiency virus (n = 12), splenectomy (n = 4), and primary immunodeficiency (n = 2). As more children are treated with immunosuppressive therapies, it is critical to identify whether they are being appropriately vaccinated for age and condition. We identified gaps in the current state of knowledge for specific vaccine types in specific immunocompromised populations.

Determinants of vaccine uptake in HIV-affected families from West Bengal

Children living with Human Immunodeficiency virus (HIV; CLH) have special vaccine needs. Determinants of household-level uptake of vaccines need to be examined in high-risk families with CLH. We previously conducted a study on the impact of Haemophilus influenzae type b conjugate vaccine and pneumococcal conjugate vaccine (PCV-13) in 125 HIV-affected families and 47 HIV-unaffected families in West Bengal. We then interviewed 99 of these 172 families who had participated in the study to understand the household-level factors that determine vaccine uptake. Sixty-four of the 99 families had one or more CLH. Within these 64 families, 30% of CLH had missed vaccines under the universal immunization program (UIP), compared to only 6% of HIV-uninfected children (HUC) (p = .001). Maternal HIV positivity in a family increased risk of missing UIP vaccines nearly five times (4.82, p = .001). Almost all families accessed UIP vaccines at local primary vaccination centers, but 14% of families experienced stigma due to HIV and avoided getting one or more vaccine doses. In contrast, in our study, 100% of HIV-affected families actively sought PCV-13 and HibCV, despite having to travel. Factors that influenced uptake included awareness generation and activation by an outreach worker and availability of vaccines on pick-up days for anti-retroviral therapy. Eighty-six percent of families strongly recommended PCV-13 to other families. To conclude, while we found that CLH have barriers to getting vaccinations, a program designed to take into consideration the obstacles that HIV-affected families face showed a high rate of vaccine uptake.

Is maternal HIV infection a risk factor for delayed or missed infant measles vaccination in western Kenya?

Measles is a highly infectious virus and one of the leading causes of childhood morbidity and mortality in areas with low immunization rates. Despite the introduction of the measles vaccine preventing about 20 million deaths between 2000 and 2016, there still is a low uptake of the vaccine, especially in low-income countries. Maternal HIV positive status is identified as one of the factors inhibiting the uptake of the measles vaccine in some settings. Using data from a Health and Demographic surveillance system (HDSS), and a Longitudinal Bio-behavioural Survey (LBBS), we assessed the effect of a mother's HIV status on a child's overall uptake of measles vaccine and timeliness in western Kenya. The findings did not show association between a mother's HIV status and a child's receipt of measles vaccine (OR = 0.84, 95% CI: 0.65, 1.08). However, higher socio-economic status (SES) was a positive factor for receipt of timely measles vaccine (OR = 1.34, 95% CI: 1.03, 1.75) for middle, (OR = 1.43, 95% CI: 1.10, 1.86) upper middle, and (OR = 1.51, 95% CI: 1.15, 1.98) higher quintiles as compared to the lower. Consequently, it is imperative to incorporate interventions that target low SES children and those that improve economic status.

Seroprevalence of measles vaccine antibody response in vertically HIV-infected children, in Morocco

BACKGROUND

The widespread use of an effective and safe vaccine to measles has substantially decreased morbidity and mortality from this epidemic. Nevertheless, HIV-infected children vaccinated against measles may develop an impaired vaccine response and remain susceptible to this disease. In Morocco, infants are routinely vaccinated against measles, regardless of their HIV serostatus. An evaluation of the immunization of these children may be of paramount importance to implement timely measures aimed at preventing measles transmission.

METHODS

In this study, we have enrolled 114 children vaccinated against measles, 50 children prenatally infected with HIV and 64 HIV-uninfected children. For all children, blood samples were taken to measure anti-measles IgG by EIA and CD4 count by flow cytometry. Additionally, HIV viral load was determined by automated real time PCR, for HIV-infected children.

RESULTS

The seroprotective rate of IgG anti-measles antibodies was significantly lower among HIV-infected children (26%) compared with HIV-uninfected children (73%) (p < 0.001). Within HIV-infected children group, the comparison of variables between children without seroprotective seroconversion to measles and those with seroprotective immunity, displayed that sex and age were not statistically different, p > 0.999 and p = 0.730, respectively. However, CD4 count was lower among children with negative serostatus to measles (23% versus 32%, p < 0.001). Furthermore, viral load was higher, with 2.91 log10 ± 2.24 versus 1.7 log10 ± 1.5 (p = 0.042). Finally, 62% of children with a negative vaccine response to measles were under HAART therapy, versus 92% (p = 0.008).

CONCLUSION

The majority of HIV-infected children vaccinated against measles develop a suboptimal seroprotective titer, and therefore remain at risk for this highly infectious disease. These data in combination with international recommendations, including recent WHO guidance on vaccination of HIV-infected children, suggest there is a need for national measures to prevent these children from measles.

Factors influencing vaccine acceptance and hesitancy in three informal settlements in Lusaka, Zambia

INTRODUCTION

Heterogeneous coverage threatens to compromise the effectiveness of immunization programs in Zambia. Demand-creation initiatives are needed to address this; however, there is incomplete understanding of why vaccine coverage is suboptimal. We investigated overarching perceptions on vaccine acceptability, hesitancy, and accessibility at three informal settlements in Lusaka, Zambia.

METHODS

Nested within a cholera vaccination uptake study, we sought to understand overarching perceptions on vaccines' hesitancy in three informal settlements in Lusaka, Zambia. We conducted 48 focus group discussions with a convenience sample of laypersons, lay healthcare workers, neighbourhood health committee members and vaccinators.

RESULTS

Both laypersons and community-based health actors reported high vaccine acceptance though several sources of hesitancy were reported. Traditional remedies, alcohol use and religious beliefs emerged as drivers of vaccine hesitancy, likely reinforced by a background of distrust towards western medicine. Also mentioned were previous adverse events, fear of injections and low perceived need for immunization. Limited understanding of how vaccines work and overlapping local terms for vaccine and other medical concepts created confusion and inaccurate views and expectations. Some reported refusing injections to avoid pain and perceived risk of infection. Discussants emphasised the importance of education and preferred mobile immunization campaigns, with weekend to reach those with poor access and delivered by a combination of professional and volunteer workers.

CONCLUSIONS

Vaccine hesitancy in Zambia is underpinned by many factors including personal experiences with vaccinations, alternative belief models, limited knowledge, deep misunderstanding about how vaccines work, and barriers to access. To overcome these, community-driven models that incorporate factual communication by professionals and operate outside of traditional hours, may help. Better research to understand community preferences for vaccine uptake could inform interventions to improve immunization coverage in Zambia.

Effect of maternal HIV status on vaccination coverage among sub-Saharan African children: A socio-ecological analysis

We investigated the relationship between maternal HIV status and uptake of the full series of three doses of diphtheria-tetanus-pertussis containing vaccines (DTP3) in sub-Saharan African children. We used data obtained from demographic and health surveys conducted in sub-Saharan Africa. We conducted meta-analysis and calculated pooled odds ratios (OR) for the association between maternal HIV status and DTP3 vaccination status for each country. A total of 4,187 out of 5,537 children of women living with HIV received DTP3 (75.6%), compared to 71,290 of 113,513 (62.8%) children of HIV negative women. National DTP3 coverage among children of HIV-positive women varied between 24% and 96% while among children of HIV negative women it was between 26% and 92%. Overall pooled result showed no significant difference in DTP3 coverage between the two groups (OR = 1.05; 95% confidence interval 0.91 – 1.22), with statistically significant heterogeneity (Chi² = 91.63, P = 0.000, I² = 71.6%). There was no significant association between DTP3 coverage and maternal HIV status in sub-Saharan Africa. However, DTP3 coverage for both HIV-exposed and non-exposed children were below the required target. Meta-regression revealed no significant association between DTP3 coverage and country characteristics (e.g. HIV prevalence among women, antiretroviral therapy coverage, gross domestic product per capita, human development index, adult literacy rate and sub-region). Improved prevention of mother-to-child transmission services might have contributed to some extent to the higher DTP3 vaccination coverage among the HIV-exposed children. There is also need to address barriers impeding uptake of vaccination among HIV-exposed and non-exposed children.

The global effect of maternal education on complete childhood vaccination: a systematic review and meta-analysis

Background

There is an established correlation between maternal education and reduction in childhood mortality. One proposed link is that an increase in maternal education will lead to an increase in health care access and vaccine uptake. Vaccinations are a central preventative child health tool, therefore demonstrating the importance of understanding factors that can improve coverage. This review aims to establish if there is a correlation between increasing maternal education and vaccine uptake and if this varies between continents, setting and time.

Methods

An electronic database search was conducted using Medline Ovid, Embase and The Cochrane Library using a combination of keywords and appropriate MeSH terms for maternal education and child vaccination. Bibliographies were also hand searched. Data was extracted and entered onto a Microsoft Excel spreadsheet and analysed using STATA 13.0 software. The primary outcome of effect size of maternal education on completion of childhood vaccinations was analysed at different levels. Secondary outcomes were explored using subgroup analyses of differences between continents, rural or urban settings, and dates.

Results

The online search yielded 3430 papers, 37 were included in this study. The analysis showed increasing child vaccination uptake with increasing maternal education. Overall, analysis showed that the odds of full childhood vaccination were 2.3 times greater in children whose mother received secondary or higher education when compared to children whose mother had no education. There was large variability in the effect size between the studies included.

Conclusions

Improving maternal education is important for increasing childhood vaccination uptake and coverage. Further research is needed in higher income countries.

Trial registration

PROSPERO Registration No: CRD42016042409.

Low vaccine coverage among children born to HIV infected women in Niamey, Niger

BACKGROUND

The effect of mother's HIV-status on child vaccination is an important public health issue in countries with high HIV prevalence. We conducted a study in a primary healthcare center located in Niamey, the capital of Niger, which offers free of charge services to HIV positive and/or underprivileged mothers, with the aim of assessing: 1) vaccination coverage for children 0-36 months old, born to HIV-infected mothers, and 2) the impact of maternal HIV status on child vaccination.

METHODS

Mothers of children less than 36 months old attending the center were interviewed, to collect information on vaccines administered to their child, and family's socio-demographic characteristics.

RESULTS

Overall, 502 children were investigated. Children of HIV-seropositive mothers were less likely to receive follow up vaccinations for Diphtheria-Tetanus-Pertussis (DTP) than those of HIV-seronegative mothers, with a prevalence ratio (PR) of 2.03 (95%CI: 1.58-2.61). Children born to HIV-seropositive mothers were less likely to miss vaccination for MMR than those born to HIV negative mothers, with a RR of 0.46 (95%CI: 0.30-0.72).

CONCLUSIONS

Vaccine coverage among children born to HIV infected mothers was rather low. It is important to favor access to vaccination programs in this population.

Risk factors for incomplete immunization in children with HIV infection

OBJECTIVE

To document the immunization rates, factors associated with incomplete immunization, and missed opportunities for immunizations in children affected by HIV presenting for routine outpatient follow-up.

METHODS

A cross-sectional study of immunization status of children affected by HIV presenting for routine outpatient care was conducted.

RESULTS

Two hundred and six HIV affected children were enrolled. The median age of children in this cohort was 6 y. One hundred ninety seven of 206 children were HIV infected, nine were HIV exposed, but indeterminate. Fifty (25 %) children had incomplete immunizations per the Universal Immunization Program (UIP) of India. Hundred percent of children had received OPV. Ninety three percent of children got their UIP vaccines from a government clinic. Children with incomplete immunization were older, median age of 8 compared to 5 (p = 0.003). Each year of maternal education increased the odds of having a child with complete UIP immunizations by 1.18 (p = 0.008)-children of mothers with 6 y of education compared to those with no education were seven times more likely to have complete UIP vaccine status. The average number of visits to the clinic by an individual child in a year was 4. This represents 200 missed opportunities for immunizations.

CONCLUSIONS

HIV infected children are at risk for incomplete immunization coverage though they regularly access medical care. Including routine immunizations, particularly catch-up immunizations in programs for HIV infected children maybe an effective way of protecting these children from vaccine preventable disease.

Undervaccination of perinatally HIV-infected and HIV-exposed uninfected children in Latin America and the Caribbean

BACKGROUND

Perinatally HIV-infected (PHIV) children may be at risk of undervaccination. Vaccination coverage rates among PHIV and HIV-exposed uninfected (HEU) children in Latin America and the Caribbean were compared.

METHODS

All PHIV and HEU children born from 2002 to 2007 who were enrolled in a multisite observational study conducted in Latin America and the Caribbean were included in this analysis. Children were classified as up to date if they had received the recommended number of doses of each vaccine at the appropriate intervals by 12 and 24 months of age. Fisher's exact test was used to analyze the data. Covariates potentially associated with a child's HIV status were considered in multivariable logistic regression modeling.

RESULTS

Of 1156 eligible children, 768 (66.4%) were HEU and 388 (33.6%) were PHIV. HEU children were significantly (P < 0.01) more likely to be up to date by 12 and 24 months of age for all vaccines examined. Statistically significant differences persisted when the analyses were limited to children enrolled before 12 months of age. Controlling for birth weight, sex, primary caregiver education and any use of tobacco, alcohol or illegal drugs during pregnancy did not contribute significantly to the logistic regression models.

CONCLUSIONS

PHIV children were significantly less likely than HEU children to be up to date for their childhood vaccinations at 12 and 24 months of age, even when limited to children enrolled before 12 months of age. Strategies to increase vaccination rates in PHIV are needed.

Barriers to immunization among children of HIV-infected mothers in Kolkata, India: a qualitative study

More than one fourth of children of HIV-infected mothers living in Kolkata city are not completely immunized by 12 months of age. This qualitative study aims to explore the barriers to immunization of these children as perceived by their caregivers and the local health care service providers. In-depth interviews were conducted after obtaining written informed consent. Audio recording and hand-recorded notes were used with permission. The transcripts were coded and analyzed using grounded theory. Deteriorating socioeconomic status, tightening of time schedule of caregivers due to illness in the family, stigma, discrimination, and lack of awareness about immunization prove to be major barriers for immunization of the HIV-exposed children. Interplay of these factors coupled with harassment and negative attitudes of service providers toward HIV-affected/HIV-infected people also impede immunization. The intervention efforts need to address these social barriers and adverse life events to improve immunization coverage.

Immunization of HIV infected children

Immunization is one of the most effective approaches to reduce morbidity and mortality in HIV infected children. However, progressive immune suppression may lead to impaired responsiveness to most of the vaccines. Besides this, there are many other areas of concern in these children including risk of diseases and safety issues with live vaccines, need for increased amount or number of doses of a particular vaccine, shortened duration of protective efficacy, need for revaccination after immune reconstitution and effect of vaccines on HIV viral replication. Published literature on safety, effectiveness and immunogenicity of vaccines in HIV infected children and status of individual vaccines with existing guidelines has been discussed in present review.

Immunisation status and its predictors among children of HIV-infected people in Kolkata

World Health Organization and United Nations International Children's Emergency Fund have strongly recommended a sustained coverage of universal immunisation among all children against tuberculosis, polio, diphtheria, pertussis, tetanus and measles. In India, these vaccines under the universal immunisation programme are made available absolutely free of cost to all children through the public health system. Information regarding immunisation coverage among HIV exposed children in India is still very limited. The objective of this study was to estimate the proportion of children of people living with HIV who had been completely immunised by the age of 12 months and to find predictors of complete immunisation. A community-based cross-sectional survey was conducted in the Kolkata Metropolitan Area between 15 June and 14 September 2009 using a pre-structured interview schedule. Data were analysed from 256 care-givers of children (85.5% response rate) whose parents were randomly selected from the Bengal Network of HIV-positive people. Multiple logistic regression was used to estimate and test associations of predictors with complete immunisation. The percentage of children of people living with HIV completely immunised at the age of 12 months was 73.0% (67.3% to 78.1%), which was not significantly different from that for all children at 12 months. Mothers having received antenatal care [OR (odds ratio): 7.29; 95% confidence intervals (CI): 2.39-22.25], mothers having postprimary education (OR: 3.37; 95% CI: 1.45-7.81), children of Hindu and Christian religion (OR: 3.74; 95% CI: 1.63-8.62), children not belonging to scheduled castes, tribes and 'other backward classes' (OR: 2.08; 95% CI: 1.02-4.25) were significant independent predictors of complete immunisation status of these children. This emphasises the imperative need for up-scaling of antenatal care among the pregnant mothers to ensure complete immunisation among their children. A special focus on girl child education should also be implemented to empower future mothers for a sustained improvement of child immunisation in the long-run. The current national immunisation programme should focus on the children from the Muslim community and those belonging to scheduled castes, tribes and other backward classes to improve coverage.

Determinants of vaccine immunity in the cohort of human immunodeficiency virus-infected children living in Switzerland

BACKGROUND

Human immunodeficiency virus (HIV)-infected children are at increased risk of infections caused by vaccine preventable pathogens, and specific immunization recommendations have been issued.

METHODS

A prospective national multicenter study assessed how these recommendations are followed in Switzerland and how immunization history correlates with vaccine immunity.

RESULTS

Among 87 HIV-infected children (mean age: 11.1 years) followed in the 5 Swiss university hospitals and 1 regional hospital, most (76%) had CD4 T cells >25%, were receiving highly active antiretroviral treatment (79%) and had undetectable viral load (60%). Immunization coverage was lower than in the general population and many lacked serum antibodies to vaccine-preventable pathogens, including measles (54%), varicella (39%), and hepatitis B (65%). The presence of vaccine antibodies correlated most significantly with having an up-to-date immunization history (P<0.05). An up-to-date immunization history was not related to age, immunologic stage, or viremia but to the referral medical center.

CONCLUSIONS

All pediatricians in charge of HIV-infected children are urged to identify missing immunizations in this high-risk population.

Population immunity to measles virus and the effect of HIV-1 infection after a mass measles vaccination campaign in Lusaka, Zambia: a cross-sectional survey

BACKGROUND

Measles control efforts are hindered by challenges in sustaining high vaccination coverage, waning immunity in HIV-1-infected children, and clustering of susceptible individuals. Our aim was to assess population immunity to measles virus after a mass vaccination campaign in a region with high HIV prevalence.

METHODS

3 years after a measles supplemental immunisation activity (SIA), we undertook a cross-sectional survey in Lusaka, Zambia. Households were randomly selected from a satellite image. Children aged 9 months to 5 years from selected households were eligible for enrolment. A questionnaire was administered to the children's caregivers to obtain information about measles vaccination history and history of measles. Oral fluid samples were obtained from children and tested for antibodies to measles virus and HIV-1 by EIA.

FINDINGS

1015 children from 668 residences provided adequate specimens. 853 (84%) children had a history of measles vaccination according to either caregiver report or immunisation card. 679 children (67%) had antibodies to measles virus, and 64 (6%) children had antibodies to HIV-1. Children with antibodies to HIV-1 were as likely to have no history of measles vaccination as those without antibodies to HIV-1 (odds ratio [OR] 1.17, 95% CI 0.57-2.41). Children without measles antibodies were more likely to have never received measles vaccine than those with antibodies (adjusted OR 2.50, 1.69-3.71). In vaccinated children, 33 (61%) of 54 children with antibodies to HIV-1 also had antibodies to measles virus, compared with 568 (71%) of 796 children without antibodies to HIV-1 (p=0.1).

INTERPRETATION

3 years after an SIA, population immunity to measles was insufficient to interrupt measles virus transmission. The use of oral fluid and satellite images for sampling are potential methods to assess population immunity and the timing of SIAs.

Immunization in patients with HIV infection: are practical recommendations possible?

The purpose of this article is to review immunization recommendations for HIV-infected individuals in resource-constrained countries, particularly in sub-Saharan Africa. Recent evidence suggests that HIV-infected children are at risk for low immunization coverage in sub-Saharan Africa. Routine immunization is recommended for these children. In comparison with immunocompetent children, recommendations for live-attenuated vaccines differ in HIV-infected children. However, limited laboratory capacity to diagnose HIV infection amongst young children prevents the implementation of these HIV-specific guidelines in resource-constrained countries. Re-immunization has been the focus of recent research in high- and middle-income countries. Findings show that children established on highly active antiretroviral therapy have suboptimal vaccine-specific immunity and may benefit from re-immunization. Before re-immunization guidelines can be formulated for resource-constrained countries, several questions should be addressed, including whether all HIV-infected children will benefit from routine re-immunization and what optimal number of vaccine doses should be administered. Pneumococcal and influenza infections are important causes of morbidity and mortality amongst HIV-infected individuals. There is compelling evidence showing that pneumococcal conjugate vaccines will protect HIV-infected and uninfected children against invasive infection. Pneumococcal conjugate vaccines should be prioritized for introduction in countries with high HIV prevalence. Although, annual influenza immunization is recommended for HIV-infected individuals, the effectiveness in Africa remains unclear. In conclusion, this brief overview has identified several limitations of current immunization policy and practice for HIV-infected individuals living in resource-constrained countries.

HIV type 1 infection is a risk factor for mortality in hospitalized Zambian children with measles

BACKGROUND

Measles remains a significant cause of vaccine-preventable mortality in sub-Saharan Africa, yet few studies have investigated risk factors for measles mortality in regions of high human immunodeficiency virus type 1 (HIV-1) prevalence.

METHODS

Between January 1998 and July 2003, children with clinically diagnosed measles who were hospitalized at the University Teaching Hospital in Lusaka, Zambia, were enrolled in an observational study. Demographic and clinical information was recorded at enrollment and at discharge or death. Measles was confirmed by detection of antimeasles virus immunoglobulin M antibodies, and HIV-1 infection was confirmed by detection of HIV-1 RNA.

RESULTS

Of 1474 enrolled children, 1227 (83%) had confirmed measles and known HIV-1 infection status. Almost one-third of the HIV-1-infected children with measles were <9 months of age, the age of routine measles vaccination, compared with one-fourth of the uninfected children (P = .07). Death occurred during hospitalization in 23 (12.2%) of the HIV-1-infected children and 45 (4.3%) of the HIV-1-uninfected children (p < .001) with measles. After adjusting for age, sex, and measles vaccination status, HIV-1 infection (odds ratio, 2.5; 95% confidence interval, 1.4-4.6), < or =8 years of maternal education (odds ratio, 2.4; 95% confidence interval, 1.2-4.8), and the presence of a desquamating rash (odds ratio, 2.2, 95% confidence interval, 1.3-3.6) were significant predictors of mortality due to measles.

CONCLUSIONS

In a region of high HIV-1 prevalence, coinfection with HIV-1 more than doubled the odds of death in hospitalized children with measles. Increased mortality among HIV-1-infected children is further evidence that greater efforts are necessary to reduce transmission of the measles virus in regions of high HIV-1 prevalence.

HIV-infected children living in Central Africa have low persistence of antibodies to vaccines used in the Expanded Program on Immunization

Background

The Expanded Program on Immunization (EPI) is the most cost-effective measures to control vaccine-preventable diseases. Currently, the EPI schedule is similar for HIV-infected children; the introduction of antiretroviral therapy (ART) should considerably prolong their life expectancy.

Methods and Principal Findings

To evaluate the persistence of antibodies to the EPI vaccines in HIV-infected and HIV-exposed uninfected children who previously received these vaccines in routine clinical practice, we conducted a cross-sectional study of children, aged 18 to 36 months, born to HIV-infected mothers and living in Central Africa. We tested blood samples for antibodies to the combined diphtheria, tetanus, and whole-cell pertussis (DTwP), the measles and the oral polio (OPV) vaccines. We enrolled 51 HIV-infected children of whom 33 were receiving ART, and 78 HIV-uninfected children born to HIV-infected women. A lower proportion of HIV-infected children than uninfected children had antibodies to the tested antigens with the exception of the OPV types 1 and 2. This difference was substantial for the measles vaccine (20% of the HIV-infected children and 56% of the HIV-exposed uninfected children, p<0.0001). We observed a high risk of low antibody levels for all EPI vaccines, except OPV types 1 and 2, in HIV-infected children with severe immunodeficiency (CD4⁺ T cells <25%).

Conclusions and Significance

Children were examined at a time when their antibody concentrations to EPI vaccines would have still not undergone significant decay. However, we showed that the antibody concentrations were lowered in HIV-infected children. Moreover, antibody concentration after a single dose of the measles vaccine was substantially lower than expected, particularly low in HIV-infected children with low CD4⁺ T cell counts. This study supports the need for a second dose of the measles vaccine and for a booster dose of the DTwP and OPV vaccines to maintain the antibody concentrations in HIV-infected and HIV-exposed uninfected children.