Reminders, Refugees, and Ramadan: Characterizing Missed Immunization Appointments among Palestinian Refugees in Jordan

There are currently over two million Palestinian refugees residing in Jordan, 370,000 of whom reside in refugee camps. Due to conflict-affiliated disease outbreaks among children in the region, the UN Relief and Works Agency for Palestine Refugees (UNRWA) has identified incomplete vaccination as a critical public health issue and has invested in the development and implementation of a text message reminder service for preventing loss-to-follow-up. Childhood immunization rates in UNRWA catchment regions are generally high, yet little is known about risk factors for missed appointments, which impose a substantial administrative burden due to the need to contact patients for rescheduling. Stronger user characterization is necessary for improved targeting and minimized cost as we develop a more robust SMS system capable of scaling across all health facilities.

This mixed-methods study prospectively recorded 6 months of immunization history among a cohort of children born in June 2014 at Taybeh Health Center in Amman. Demographic information was collected at the time of birth, and caregivers of cohort members were invited to participate in interviews that assessed immunization knowledge, preferences, decision-making, and experience with the SMS reminder system. Patients were more likely to significantly delay appointments during the Ramadan holiday and for doses further from the child date of birth. Future policies that might bridge these gaps include targeting pre-appointment SMS reminders to high-risk patients, implementing holiday shifts in clinic hours, and regularly updating patient contact information.

Isolation of HIV-1-neutralizing mucosal monoclonal antibodies from human colostrum.

BACKGROUND: Generation of potent anti-HIV antibody responses in mucosal compartments is a potential requirement of a transmission-blocking HIV vaccine. HIV-specific, functional antibody responses are present in breast milk, and these mucosal antibody responses may play a role in protection of the majority of HIV-exposed, breastfeeding infants. Therefore, characterization of HIV-specific antibodies produced by B cells in milk could guide the development of vaccines that elicit protective mucosal antibody responses. METHODS: We isolated B cells from colostrum of an HIV-infected lactating woman with a detectable neutralization response in milk and recombinantly produced and characterized the resulting HIV-1 Envelope (Env)-specific monoclonal antibodies (mAbs). RESULTS: The identified HIV-1 Env-specific colostrum mAbs, CH07 and CH08, represent two of the first mucosally-derived anti-HIV antibodies yet to be reported. Colostrum mAb CH07 is a highly-autoreactive, weakly-neutralizing gp140-specific mAb that binds to linear epitopes in the gp120 C5 region and gp41 fusion domain. In contrast, colostrum mAb CH08 is a nonpolyreactive CD4-inducible (CD4i) gp120-specific mAb with moderate breadth of neutralization. CONCLUSIONS: These novel HIV-neutralizing mAbs isolated from a mucosal compartment provide insight into the ability of mucosal B cell populations to produce functional anti-HIV antibodies that may contribute to protection against virus acquisition at mucosal surfaces.

Potent functional antibody responses elicited by HIV-I DNA priming and boosting with heterologous HIV-1 recombinant MVA in healthy Tanzanian adults.

UNLABELLED: Vaccine-induced HIV antibodies were evaluated in serum samples collected from healthy Tanzanian volunteers participating in a phase I/II placebo-controlled double blind trial using multi-clade, multigene HIV-DNA priming and recombinant modified vaccinia Ankara (HIV-MVA) virus boosting (HIVIS03). The HIV-DNA vaccine contained plasmids expressing HIV-1 gp160 subtypes A, B, C, Rev B, Gag A, B and RTmut B, and the recombinant HIV-MVA boost expressed CRF01_AE HIV-1 Env subtype E and Gag-Pol subtype A. While no neutralizing antibodies were detected using pseudoviruses in the TZM-bl cell assay, this prime-boost vaccination induced neutralizing antibodies in 83% of HIVIS03 vaccinees when a peripheral blood mononuclear cell (PBMC) assay using luciferase reporter-infectious molecular clones (LucR-IMC) was employed. The serum neutralizing activity was significantly (but not completely) reduced upon depletion of natural killer (NK) cells from PBMC (p=0.006), indicating a role for antibody-mediated Fcγ-receptor function. High levels of antibody-dependent cellular cytotoxicity (ADCC)-mediating antibodies against CRF01_AE and/or subtype B were subsequently demonstrated in 97% of the sera of vaccinees. The magnitude of ADCC-mediating antibodies against CM235 CRF01_AE IMC-infected cells correlated with neutralizing antibodies against CM235 in the IMC/PBMC assay. In conclusion, HIV-DNA priming, followed by two HIV-MVA boosts elicited potent ADCC responses in a high proportion of Tanzanian vaccinees. Our findings highlight the potential of HIV-DNA prime HIV-MVA boost vaccines for induction of functional antibody responses and suggest this vaccine regimen and ADCC studies as potentially important new avenues in HIV vaccine development. TRIAL REGISTRATION: Controlled-Trials ISRCTN90053831 The Pan African Clinical Trials Registry ATMR2009040001075080 (currently PACTR2009040001075080).

Maternal Effects of Respiratory Syncytial Virus Infection during Pregnancy.

Given the illness and deaths caused by respiratory syncytial virus (RSV) infection during the first year of life, preventing infant RSV infections through maternal vaccination is intriguing. However, little is known about the extent and maternal effects of RSV infection during pregnancy. We describe 3 cases of maternal RSV infection diagnosed at a US center during winter 2014. Case-patient 1 (26 years old, week 33 of gestation) received a diagnosis of RSV infection and required mechanical ventilation. Case-patient 2 (27 years old, week 34 of gestation) received a diagnosis of infection with influenza A(H1N1) virus and RSV and required mechanical ventilation. Case-patient 3 (21 years old, week 32 of gestation) received a diagnosis of group A streptococcus pharyngitis and RSV infection and was monitored as an outpatient. Clarifying the effects of maternal RSV infection could yield valuable insights into potential maternal and fetal benefits of an effective RSV vaccination program.

Potential To Streamline Heterologous DNA Prime and NYVAC/Protein Boost HIV Vaccine Regimens in Rhesus Macaques by Employing Improved Antigens.

UNLABELLED: In a follow-up to the modest efficacy observed in the RV144 trial, researchers in the HIV vaccine field seek to substantiate and extend the results by evaluating other poxvirus vectors and combinations with DNA and protein vaccines. Earlier clinical trials (EuroVacc trials 01 to 03) evaluated the immunogenicity of HIV-1 clade C GagPolNef and gp120 antigens delivered via the poxviral vector NYVAC. These showed that a vaccination regimen including DNA-C priming prior to a NYVAC-C boost considerably enhanced vaccine-elicited immune responses compared to those with NYVAC-C alone. Moreover, responses were improved by using three as opposed to two DNA-C primes. In the present study, we assessed in nonhuman primates whether such vaccination regimens can be streamlined further by using fewer and accelerated immunizations and employing a novel generation of improved DNA-C and NYVAC-C vaccine candidates designed for higher expression levels and more balanced immune responses. Three different DNA-C prime/NYVAC-C+ protein boost vaccination regimens were tested in rhesus macaques. All regimens elicited vigorous and well-balanced CD8(+)and CD4(+)T cell responses that were broad and polyfunctional. Very high IgG binding titers, substantial antibody-dependent cellular cytotoxicity (ADCC), and modest antibody-dependent cell-mediated virus inhibition (ADCVI), but very low neutralization activity, were measured after the final immunizations. Overall, immune responses elicited in all three groups were very similar and of greater magnitude, breadth, and quality than those of earlier EuroVacc vaccines. In conclusion, these findings indicate that vaccination schemes can be simplified by using improved antigens and regimens. This may offer a more practical and affordable means to elicit potentially protective immune responses upon vaccination, especially in resource-constrained settings. IMPORTANCE: Within the EuroVacc clinical trials, we previously assessed the immunogenicity of HIV clade C antigens delivered in a DNA prime/NYVAC boost regimen. The trials showed that the DNA prime crucially improved the responses, and three DNA primes with a NYVAC boost appeared to be optimal. Nevertheless, T cell responses were primarily directed toward Env, and humoral responses were modest. The aim of this study was to assess improved antigens for the capacity to elicit more potent and balanced responses in rhesus macaques, even with various simpler immunization regimens. Our results showed that the novel antigens in fact elicited larger numbers of T cells with a polyfunctional profile and a good Env-GagPolNef balance, as well as high-titer and Fc-functional antibody responses. Finally, comparison of the different schedules indicates that a simpler regimen of only two DNA primes and one NYVAC boost in combination with protein may be very efficient, thus showing that the novel antigens allow for easier immunization protocols.

Fabrication of Poly (D,L-Lactic-Co-Glycolic Acid) Microparticles for Improved Human Papillomavirus Vaccine Delivery

Human papillomavirus (HPV) is the leading cause of cervical cancer and the most prevalent sexually transmitted disease worldwide. HPV vaccines require a multi-dose regimen to provide immunity, contributing to low patient compliance. We addressed this problem by formulating biodegradable poly(D,L-lactic-co-glycolic acid) (PLGA) microparticles and assessing their viability for use in controlled-release vaccines. We hypothesized that we could alter fabrication parameters to produce 1-10 μm microparticles in order to encapsulate ovalbumin (OVA) and HPV virus-like particles (VLPs). Microparticles were fabricated using a double emulsion method and used to elicit an immune response in JAWSII cells. Our results contribute to knowledge of vaccine delivery mechanisms and controlled-release technology, and could contribute to the creation of a viable controlled-release HPV vaccine.

HBHA-specific CD4+, CD8+ and CD4+CD25+FOXP3+ T cells as biomarkers for protection and disease in human tuberculosis

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Humoral and B-cell memory responses in children five years after pertussis acellular vaccine priming.

The resurgence of pertussis suggests the need for greater efforts in understanding the long-lasting protective responses induced by vaccination. In this paper we dissect the persistence of humoral and B-cell memory responses induced by primary vaccination with two different acellular pertussis (aP) vaccines, hexavalent Hexavac(®) vaccine (Hexavac) (Sanofi Pasteur MSD) and Infanrix hexa(®) (Infanrix) (GlaxoSmithKline Biologicals). We evaluated the specific immune responses in the two groups of children, 5 years after primary vaccination by measuring the persistence of IgG and antibody secreting cells (ASC) specific for vaccine antigens. Part of the enrolled children received only primary vaccination, while others had the pre-school boost dose. A similar level of antigen-specific IgG and ASC was found in Infanrix and Hexavac vaccinated children. The mean IgG levels were significantly higher in children that received the pre-school boost as compared with children that did not receive the boost dose. A longer persistence after the pre-school boost of IgG-Pertussis Toxin (PT) and IgG-pertactin levels was observed in Infanrix primed children, but it was not statistically significant. More than 80% of children presented a positive ASC B memory response. Around 50% of children still presented protective IgG-PT levels which are reduced to 36% in no-boosted children. The pre-school booster dose restores the percentage of protected children above 50%. In conclusion our data underline the importance of giving a booster dose 5 years after primary vaccination and suggest the need for a new vaccine able to induce a long lasting protective response.

Modulation of the infant immune responses by the firts pertussis vaccine administrations

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Identification of pertussis-specific effector memory T cells in preschool children

Whooping cough remains a problem despite vaccination, and worldwide resurgence of pertussis is evident. Since cellular immunity plays a role in long-term protection against pertussis, we studied pertussis-specific T-cell responses. Around the time of the preschool acellular pertussis (aP) booster dose at 4 years of age, T-cell memory responses were compared in children who were primed during infancy with either a whole-cell pertussis (wP) or an aP vaccine. Peripheral blood mononuclear cells (PBMCs) were isolated and stimulated with pertussis vaccine antigens for 5 days. T cells were characterized by flow-based analysis of carboxyfluorescein succinimidyl ester (CFSE) dilution and CD4, CD3, CD45RA, CCR7, gamma interferon (IFN-γ), and tumor necrosis factor alpha (TNF-α) expression. Before the aP preschool booster vaccination, both the proliferated pertussis toxin (PT)-specific CD4⁺ and CD8⁺ T-cell fractions (CFSE^dim) were higher in aP-than in wP-primed children. Post-booster vaccination, more pertussis-specific CD4⁺ effector memory cells (CD45RA^- CCR7^-) were induced in aP-primed children than in those primed with wP. The booster vaccination did not appear to significantly affect the T-cell memory subsets and functionality in aP-primed or wP-primed children. Although the percentages of Th1 cytokine-producing cells were alike in aP- and wP-primed children pre-booster vaccination, aP-primed children produced more Th1 cytokines due to higher numbers of proliferated pertussis-specific effector memory cells. At present, infant vaccinations with four aP vaccines in the first year of life result in pertussis-specific CD4⁺ and CD8⁺ effector memory T-cell responses that persist in children until 4 years of age and are higher than those in wP-primed children. The booster at 4 years of age is therefore questionable; this may be postponed to 6 years of age.

Bordetella pertussis infection in 2-month-old infants promotes type 1 T cell responses.

Neonatal immaturity of the immune system is currently believed to generally limit the induction of immune responses to vaccine Ags and to skew them toward type 2 responses. We demonstrated here that Bordetella pertussis infection in very young infants (median, 2 mo old) as well as the first administration of whole-cell pertussis vaccine induces B. pertussis Ag-specific IFN-gamma secretion by the PBMC of these infants. IFN-gamma was secreted by both CD4(+) and CD8(+) T lymphocytes, and the levels of Ag-induced IFN-gamma secretion did not correlate with the age of the infants. Appearance of the specific Th-1 cell-mediated immunity was accompanied by a general shift of the cytokine secretion profile of these infants toward a stronger Th1 profile, as evidenced by the response to a polyclonal stimulation. We conclude that the immune system of 2-mo-old infants is developmentally mature enough to develop Th1 responses in vivo upon infection by B. pertussis or vaccination with whole-cell pertussis vaccines.

Heparin-binding hemagglutinin, from an extrapulmonary dissemination factor to a powerful diagnostic and protective antigen against tuberculosis.

Interactions of Mycobacterium tuberculosis with macrophages have long been recognized to be crucial to the pathogenesis of tuberculosis. The role of non-phagocytic cells is less well known. We have discovered a M. tuberculosis surface protein that interacts specifically with non-phagocytic cells, expresses hemagglutination activity and binds to sulfated glycoconjugates. It is therefore called heparin-binding hemagglutinin (HBHA). HBHA-deficient M. tuberculosis mutant strains are significantly impaired in their ability to disseminate from the lungs to other tissues, suggesting that the interaction with non-phagocytic cells, such as pulmonary epithelial cells, may play an important role in the extrapulmonary dissemination of the tubercle bacillus, one of the key steps that may lead to latency. Latently infected human individuals mount a strong T cell response to HBHA, whereas patients with active disease do not, suggesting that HBHA is a good marker for the immunodiagnosis of latent tuberculosis, and that HBHA-specific Th1 responses may contribute to protective immunity against active tuberculosis. Strong HBHA-mediated immuno-protection was shown in mouse challenge models. HBHA is a methylated protein and its antigenicity in latently infected subjects, as well as its protective immunogenicity strongly depends on the methylation pattern of HBHA. In both mice and man, the HBHA-specific IFN-gamma was produced by both the CD4(+) and the CD8(+) T cells. Furthermore, the HBHA-specific CD8(+) T cells expressed bactericidal and cytotoxic activities to mycobacteria-infected macrophages. This latter activity is most likely perforin mediated. Together, these observations strongly support the potential of methylated HBHA as an important component in future, acellular vaccines against tuberculosis.

Modulation of the infant immune responses by the first pertussis vaccine administrations.

Many efforts are currently made to prepare combined vaccines against most infectious pathogens, that may be administered early in life to protect infants against infectious diseases as early as possible. However, little is known about the general immune modulation induced by early vaccination. Here, we have analyzed the cytokine secretion profiles of two groups of 6-month-old infants having received as primary immunization either a whole-cell (Pw) or an acellular (Pa) pertussis vaccine in a tetravalent formulation of pertussis-tetanus-diphtheria-poliomyelitis vaccines. Both groups of infants secreted IFN-gamma in response to the Bordetella pertussis antigens filamentous haemagglutinin and pertussis toxin, and this response was correlated with antigen-specific IL-12p70 secretion, indicating that both pertussis vaccines induced Th1 cytokines. However, Pa recipients also developed a strong Th2-type cytokine response to the B. pertussis antigens, as noted previously. In addition, they induced Th2-type cytokines to the co-administrated antigen tetanus toxoïd, as well as to the food antigen beta-lactoglobulin. Furthermore, the general cytokine profile of the Pa recipients was strongly Th2-skewed at 6 months, as indicated by the cytokines induced by the mitogen phytohaemagglutinin. These data demonstrate that the cytokine profile of 6-month-old infants is influenced by the type of formulation of the pertussis vaccine they received at 2, 3 and 4 months of life. Large prospective studies would be warranted to evaluate the possible long-term consequences of this early modulation of the cytokine responses in infants.

HBHA-specific IFN-{gamma} Synthesis at the Site of Infection during Active Tuberculosis in Humans.

RATIONALE: Tuberculosis (TB) remains a major cause of mortality. A better understanding of the immune responses to mycobacterial antigens may be helpful to develop improved vaccines and diagnostics. OBJECTIVE: The mycobacterial antigen heparin-binding-hemagglutinin (HBHA) induces strong interferon-gamma (IFN-gamma) responses by circulating lymphocytes from Mycobacterium tuberculosis latently infected subjects, and low responses associated with CD4(+) regulatory T (Treg) cells in TB patients. Here, we investigated HBHA-specific IFN-gamma responses at the site of the TB disease. METHODS: Bronchoalveolar lavages, pleural fluids and blood were prospectively collected from 61 patients with a possible diagnosis of pulmonary and/or pleural TB. HBHA-specific IFN-gamma production was analyzed by flow cytometry and ELISA. The suppressive effect of pleural Treg cells was investigated by depletion experiments. MEASUREMENTS AND MAIN RESULTS: The percentages of HBHA-induced IFN-gamma(+) alveolar and pleural lymphocytes were higher for pulmonary (P<0.0001) and for pleural (P<0.01) TB than for non-TB controls. Local CD4(+) and CD8(+) T cells produced the HBHA-specific IFN-gamma. This local secretion was not suppressed by Treg lymphocytes, contrasting with previously reported data on circulating lymphocytes. CONCLUSION: TB patients display differential effector and regulatory T cell responses to HBHA in local and circulating lymphocytes with a predominant effector CD4(+) and CD8(+) response locally, compared to a predominant Treg response among circulating lymphocytes. These findings may be helpful for the design of new vaccines against TB, and the detection of HBHA-specific T cells at the site of the infection may be a promising tool for the rapid diagnosis of active TB.

Different T cell memory in preadolescents after whole-cell or acellular pertussis vaccination.

To better understand vaccine-induced protection and its potential failure in light of recent whooping cough resurgence, we evaluated quantity as well as quality of memory T cell responses in B. pertussis-vaccinated preadolescent children. Using a technique based on flow cytometry to detect proliferation, cytokine production and phenotype of antigen-specific cells, we evaluated residual T cell memory in a cohort of preadolescents who received a whole-cell pertussis (wP; n=11) or an acellular pertussis vaccine (aP; n=13) during infancy, and with a median of 4 years elapsed from the last pertussis booster vaccine, which was aP for all children. We demonstrated that B. pertussis-specific memory T cells are detectable in the majority of preadolescent children several years after vaccination. CD4(+) and CD8(+) T cell proliferation in response to pertussis toxin and/or filamentous hemagglutinin was detected in 79% and 60% of the children respectively, and interferon-γ or tumor necrosis factor-α producing CD4(+) T cells were detected in 65% and 53% of the children respectively. Phenotyping of the responding cells showed that the majority of antigen-specific cells, whether defined by proliferation or cytokine production, were CD45RA(-)CCR7(-) effector memory T cells. Although the time since the last booster vaccine was significantly longer for wP-compared to aP-vaccinated children, their proliferation capacity in response to antigenic stimulation was comparable, and more children had a detectable cytokine response after wP- compared to aP-vaccination. This study supports at the immunological level recent epidemiological studies indicating that infant vaccination with wP induces longer lasting immunity than vaccination with aP-vaccines.