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

Evaluation of effectiveness, safety and cost-benefit of the 23- valent pneumococcal capsular polysaccharide vaccine for HIV-Infected patients

INTRODUCTION

Due to the lack of understanding of the protective effects and safety of 23-valent pneumococcal polysaccharide vaccine (PPV23) in immune-deficient populations, the vaccination rate of PPV23 among HIV-infected patients is still very low in China. The main objectives of this study were to determine whether the efforts to assess measures for the prevention of pneumococcal pneumonia are still worthwhile, and provide designated vaccination program of HIV-infected persons for government policy based on.

METHODS

60 HIV-infected adults in Lanshan county who had never been vaccinated with any pneumococcal vaccine were enrolled in this study, voluntary vaccination of PPV23 and One-year follow-up after vaccination can be completed.

RESULT

76.67% patients (46/60) had serologic response at 12 months after vaccine, CD4 count(≤500 cells/ul or > 500 cells/ul) and Month from diagnosis to first antiviral therapy (≤1 month or > 1 month) were related to antibody responses (p < 0.05).In this study, PPV23 was well tolerated, no adversereaction was reported.11 Streptococcus pneumoniae pneumonia (9.17%,11/120) occurred in the Unvaccinated group and 1 case(1.67%,1/60)in the vaccination group within one year after vaccination(Fisher's exact probability, P = 0.225). The VE was 81.79%. The per capita benefit was 39.32 dollars, thebenefit-costratio = 1.19. There are significant statistical differences between the vaccinated group and the non-vaccinated group in outpatient costs (p < 0.05, 95 %CI: 9.29-32.11), Medicine costs (p = 0.017, 95 %CI: 2.47-24.44), and disease related indirect costs (p = 0.038, 95 %CI: 0.93-33.63) within one year of vaccination.

CONCLUSION

Our study results showed that PPV23 can be safely and effectively administered to HIV-1 infected individuals and effectively preventing Streptococcal pneumonia. Considering the cost-benefit of vaccination among HIV-infected persons, as it has been reported in our study, it is necessary to promote the widespread use of the vaccine among HIV-infected persons in the future.

Estimating the contribution of HIV-infected adults to household pneumococcal transmission in South Africa, 2016–2018: A hidden Markov modelling study

Human immunodeficiency virus (HIV) infected adults are at a higher risk of pneumococcal colonisation and disease, even while receiving antiretroviral therapy (ART). To help evaluate potential indirect effects of vaccination of HIV-infected adults, we assessed whether HIV-infected adults disproportionately contribute to household transmission of pneumococci. We constructed a hidden Markov model to capture the dynamics of pneumococcal carriage acquisition and clearance observed during a longitudinal household-based nasopharyngeal swabbing study, while accounting for sample misclassifications. Households were followed-up twice weekly for approximately 10 months each year during a three-year study period for nasopharyngeal carriage detection via real-time PCR. We estimated the effect of participant’s age, HIV status, presence of a HIV-infected adult within the household and other covariates on pneumococcal acquisition and clearance probabilities. Of 1,684 individuals enrolled, 279 (16.6%) were younger children (<5 years-old) of whom 4 (1.5%) were HIV-infected and 726 (43.1%) were adults (≥18 years-old) of whom 214 (30.4%) were HIV-infected, most (173, 81.2%) with high CD4+ count. The observed range of pneumococcal carriage prevalence across visits was substantially higher in younger children (56.9–80.5%) than older children (5–17 years-old) (31.7–50.0%) or adults (11.5–23.5%). We estimate that 14.4% (95% Confidence Interval [CI]: 13.7–15.0) of pneumococcal-negative swabs were false negatives. Daily carriage acquisition probabilities among HIV-uninfected younger children were similar in households with and without HIV-infected adults (hazard ratio: 0.95, 95%CI: 0.91–1.01). Longer average carriage duration (11.4 days, 95%CI: 10.2–12.8 vs 6.0 days, 95%CI: 5.6–6.3) and higher median carriage density (622 genome equivalents per millilitre, 95%CI: 507–714 vs 389, 95%CI: 311.1–435.5) were estimated in HIV-infected vs HIV-uninfected adults. The use of ART and antibiotics substantially reduced carriage duration in all age groups, and acquisition rates increased with household size. Although South African HIV-infected adults on ART have longer carriage duration and density than their HIV-uninfected counterparts, they show similar patterns of pneumococcal acquisition and onward transmission.

We assessed the contribution of HIV-infected adults to household pneumococcal transmission by applying a hidden Markov model to pneumococcal cohort data comprising 115,595 nasopharyngeal samples from 1,684 individuals in rural and urban settings in South Africa. We estimated 14.4% of sample misclassifications (false negatives), representing 85.6% sensitivity of a test that was used to detect pneumococcus. Pneumococcal carriage prevalence and acquisition rates, and average duration were usually higher in younger or older children than adults. The use of ART and antibiotics reduced the average carriage duration across all age and HIV groups, and carriage acquisition risks increased in larger household sizes. Despite the longer average carriage duration and higher median carriage density in HIV-infected than HIV-uninfected adults, we found similar carriage acquisition and onward transmission risks in the dual groups. These findings suggest that vaccinating HIV-infected adults on ART with PCV would reduce their risk for pneumococcal disease but may add little to the indirect protection against carriage of the rest of the population.

Levels of vaccination coverage among HIV-exposed children in China: a retrospective study

Background

Vaccination is crucial for human immunodeficiency virus (HIV)-exposed children because of their increased risk of morbidity and mortality from various vaccine-preventable diseases. However, studies have shown that they are at high risk of incomplete vaccination. Although China has developed prevention of mother-to-child transmission (PMTCT) of HIV programs substantially over the past decades, few studies have investigated the immunization levels of Chinese HIV-exposed children. Therefore, we aimed to evaluate vaccination coverage and its associated factors among HIV-exposed children in China during 2016‒2018.

Methods

We conducted a retrospective cohort review of all cases of Chinese HIV-exposed children born between July 1, 2016 and June 30, 2018 recorded in the Chinese information system on PMTCT. The vaccination coverage indicators refer to the percentage of children who received recommended basic vaccines, including Bacillus Calmette-Guérin (BCG), hepatitis B (HepB), polio, measles-containing vaccine (MCV), and diphtheria-tetanus-pertussis-containing (DTP) vaccine. Univariate and multivariate logistic regression analyses expressed as crude odds ratios (cORs) and adjusted odds ratios (aORs), each with 95% confidence intervals (95% CI), were performed to compare the proportional differences of factors associated with vaccine coverage.

Results

Among the enrolled 10 033 children, the vaccination rate was 54.1% for BCG, 84.5% for complete HepB vaccination, 54.5% for complete polio vaccination, 51.3% for MCV, and 59.5% for complete DTP vaccination. Children with perinatally acquired HIV (PHIV) were 2.46‒3.82 times less likely to be vaccinated than HIV-exposed uninfected children. Multivariate logistic regression indicated that children of Han ethnicity (aOR = 1.33‒2.04), children with early infant diagnosis (EID) of HIV (aOR = 1.86‒3.17), and children whose mothers had better education (college or above, aOR = 1.63‒2.51) had higher odds of being vaccinated. Most of the deceased children (aOR = 4.28‒21.55) missed vaccination, and PHIV (aOR = 2.46‒3.82) significantly affected immunization.

Conclusions

Chinese HIV-exposed children had low vaccination coverage, which is a serious health challenge that needs to be addressed thoroughly. Interventions should be developed with a focus on minority HIV-exposed children whose mothers do not have formal education. Particularly, more attention should be paid to EID to increase access to immunization.

Graphical abstract

Vaccine strategies to reduce the burden of pneumococcal disease in HIV-infected adults in Africa

INTRODUCTION

Streptococcus pneumoniae is the leading cause of invasive bacterial disease, globally. Despite antiretroviral therapy, adults infected with human immunodeficiency virus (HIV) are also at high risk of pneumococcal carriage and disease. Pneumococcal conjugate vaccines (PCVs) provide effective protection against vaccine serotype (VT) carriage and disease in children, and have been introduced worldwide, including most HIV-affected low- and middle-income countries. Unlike high-income countries, the circulation of VT persists in the PCV era in some low-income countries and results in a continued high burden of pneumococcal disease in HIV-infected adults. Moreover, no routine vaccination that directly protects HIV-infected adults in such settings has been implemented.

AREAS COVERED

Nonsystematic review on the pneumococcal burden in HIV-infected adults and vaccine strategies to reduce this burden.

EXPERT OPINION

We propose and discuss the relative merit of changing the infant PCV program to use (1a) a two prime plus booster dose schedule, (1b) a two prime plus booster dose schedule with an additional booster dose at school entry, to directly vaccinate (2a) HIV-infected adults or vaccinating (2b) HIV-infected pregnant women for direct protection, with added indirect protection to the high-risk neonates. We identify key knowledge gaps for such an evaluation and propose strategies to overcome them.

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.

Non-uptake of childhood vaccination among the children of HIV-infected mothers in sub-Saharan Africa: A multilevel analysis

The aim of this study was to develop and test models for non–uptake of three doses of diphtheria-tetanus-pertussis containing vaccines (DTP3) among children of women living with HIV in sub-Saharan Africa. The study used demographic and health survey data from 27 sub-Saharan African countries that have the required HIV and immunization data sets. Multivariable logistic regression models were used to assess the relationship between individual and contextual factors associated with non-uptake of DTP3 among the children. At the individual level, the odds of non-uptake of DTP3 decreased with formal education, increasing age and access to media. The full model shows that the odds of non-uptake of DTP3 is increased among unemployed women, those living in communities with high illiteracy rate and in countries with low adult literacy level. For a child who moved to another country or community with a higher probability of DTP3 non-uptake, the median increase for the odds of DTP3 non-uptake would be 2.24% and 1.22% respectively for country and community. This study shows that individual and contextual factors contributed significantly to non-uptake of DTP3 among the children of women living with HIV. Interventions should be focused on women living with HIV who are young mothers, unemployed women, those without formal education, individuals living in communities with high illiteracy rate and in countries with low adult literacy rate. The use of mass media tools and creation of more employment opportunities for HIV-infected women could improve vaccination coverage among their children.

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.

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.

Pneumococcal immunization in immunocompromised hosts: where do we stand?

Immunocompromised patients are all at risk of invasive pneumococcal disease, of different degrees and timings. However, considerable progress in pneumococcal immunization over the last 30 years should benefit these patients. The 23-valent polysaccharide vaccine has been widely evaluated in these populations, but due to its low immunogenicity, its efficacy is sub-optimal, or even low. The principle of the conjugate vaccine is that, through the protein conjugation with the polysaccharide, the vaccine becomes more immunogenic, T-cell dependent, and thus providing a better early response and a boost effect. The 7-valent conjugate vaccine has been the first one to be evaluated in different immunocompromised populations. We review here the efficacy and safety of the different antipneumococcal vaccines in cancer, transplant and HIV-positive patients and propose a critical appraisal of the current guidelines.

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.

Safety, immunogenicity and efficacy of pneumococcal conjugate vaccine in HIV-infected individuals

Streptococcus pneumoniae is the leading bacterial opportunistic infection in HIV-infected individuals. Anti-retroviral treatment (ART) of HIV-infected individuals reduces their risk of invasive pneumococcal disease (IPD), however, it remains 20- to 40-fold greater compared with age-matched general population. This review summarizes the available published data on the immunogenicity, safety and efficacy of pneumococcal polysaccharide-protein conjugate vaccines (PCV) in HIV-infected children and adults.   Several studies have demonstrated that PCV are safe in the HIV-infected persons. Although PCV are immunogenic in HIV-infected infants, the antibodies produced are functionally impaired, there is possibly a lack or loss of anamnestic responses and immunity declines in later life However, quantitative and qualitative antibody responses to PCV in HIV-infected infants are enhanced when vaccination occurs whilst on ART, as well as if vaccination occurs when the CD4+ cell percentage is ≥ 25% and if the nadir CD4+ is > 15%. Although the efficacy of PCV was lower, the vaccine preventable burden of hospitalization for IPD and clinical pneumonia were 18-fold and 9-fold greater, respectively, in HIV-infected children compared with -uninfected children. In HIV-infected adults, PCV vaccination induces more durable and functional antibody responses in individuals on ART at the time of vaccination than in ART-naive adults, independently of baseline CD4+ cell count, although there does not appear to be much benefit from a second-dose of PCV. PCV has also been shown to reduce the risk of recurrent IPD by 74% in HIV-infected adults not on ART, albeit, also with subsequent decline in immunity and protection.

Levels of childhood vaccination coverage and the impact of maternal HIV status on child vaccination status in rural KwaZulu-Natal, South Africa*

OBJECTIVES

To analyse coverage of childhood vaccinations in a rural South African population and investigate whether maternal HIV status is associated with children's vaccination status.

METHODS

2 431 children with complete information, 12-23 months of age at some point during the period January 2005 through December 2006 and resident in the Africa Centre Demographic Surveillance Area at the time of their birth were investigated. We examined the relationship between maternal HIV status and child vaccination status for five vaccinations [Bacillus Calmette-Guérin (BCG), diphtheria-tetanus-pertussis (DTP3), poliomyelitis (polio3), hepatitis B (HepB3), and measles] in multiple logistic regressions, controlling for household wealth, maternal age, maternal education and distances to roads, fixed and mobile clinics.

RESULTS

Coverage of the five vaccinations ranged from 89.3% (95% CI 81.7-93.9) for BCG to 77.3% (67.1-83.6) for measles. Multivariably, maternal HIV-positive status was significantly associated with lower adjusted odds ratios (AOR) of child vaccination for all vaccines [(AOR) 0.60-0.74, all P < or = 0.036] except measles (0.75, P = 0.073), distance to mobile clinic was negatively associated with vaccination status (all P < or = 0.029), household wealth was positively (all P < or = 0.013) and distance to nearest road negatively (all P < or = 0.004) associated with vaccination status.

CONCLUSION

Positive maternal HIV status independently reduces children's probability to receive child vaccinations, which likely contributes to the morbidity and mortality differential between children of HIV-positive and HIV-negative mothers. As a means of increasing vaccination coverage, policy makers should consider increasing the number of mobile clinics in this and similar communities in rural Africa.