Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Immunization”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 919 records · Page 51Linked to original sources
PubMed1972

Induction of immunity and tolerance in vitro by hapten protein conjugates. 3. Hapten inhibition studies of antigen binding to B cells in immunity and tolerance.

The capacity of dissociated spleen cell suspensions to be immunized by dinitrophenylated polymeric flagellin (DNP POL), in the absence of thymus-dependent lymphocytes or macrophages, provided a simple experimental system to investigate the mechanism of binding of antigen molecules to nonthymus-dependent lymphocyte (B cell) receptors during the induction of immunity or tolerance. Various nonimmunogenic DNP compounds were used to inhibit the anti-DNP response to DNP POL. By performing inhibition experiments of brief duration at 4 degrees C, it was established that the inhibition of the anti-DNP response by nonimmunogenic compounds was due to competitive blockade of receptors, and not tolerance or receptor modulation. It was found that univalent DNP compounds were much less efficient inhibitors of the antibody response than multivalent DNP conjugates. The difference in inhibitory capacity between univalent and multivalent DNP human globulin (DNP HgG) suggested the importance of interaction with both combining sites of a single receptor antibody molecule. Nonimmunogenic highly conjugated DNP(3)POL was a more efficient inhibitor of the anti-DNP response to immunogenic DNP(1)POL than DNP(12)HgG, indicating that interactions at more than one receptor molecule are involved in immunization of B cells. Recent demonstrations of the rapid metabolic turnover of receptor antibody molecules suggests that the requirement for multipoint binding (to different receptors) may simply be to maintain the antigen at the cell surface in a dynamic system. Competitive inhibition experiments were also performed to investigate the mechanism of binding of DNP(3)POL in the induction of B cell tolerance. It was found that monovalent DNP compounds or multivalent DNP(12)HgG did not prevent the induction of tolerance, unlike their capacity to inhibit immunity, suggesting that a tolerance-inducing antigen binds more avidly to the cell membrane than an immunogen. The inhibition data obtained here, together with prior results describing the differential immunogenicity of DNP conjugates of different structure, and the importance of epitope density on DNP POL conjugates, permit certain conclusions about the details of antigen-receptor interaction in immunity and tolerance. Distinctions between the mechanisms of immune and tolerance induction are discussed.

Animals↗
PubMedDate not supplied

Immune responses to herpes simplex virus in guinea pigs (footpad model) and mice immunized with vaccinia virus recombinants containing herpes simplex virus glycoprotein D.

Vaccinia virus recombinants containing the herpes simplex virus (HSV) gene for glycoprotein D type 1 (gD-1) under control of an early (VP176) or late (VP254) vaccinia virus promoter or for HSV glycoprotein type 2 (gD-2) under control of the early promoter (VP221) were studied for their ability to induce protective immunity to HSV-2 in the guinea pig model of cutaneous recurrent disease and the mouse model of fatal disease. Titers of HSV-specific neutralizing antibody were similar in the two groups of immunized animals, but HSV-specific T cell responses were significantly higher in VP176-immunized than in VP254-immunized animals, as determined by lymphoproliferation (P less than .005) and delayed-type hypersensitivity (P less than .01) responses. The reduced responses correlated with poor expression of the gD protein and its impaired processing in infected antigen-presenting cells (splenic adherent and epidermal cells). VP176 immunization protected against primary (P much less than .001) and recurrent (P much less than .001) cutaneous HSV-2 lesions and ganglionic latency (62% protection) in the guinea pig and against zosteriform skin lesions and fatal disease in the mouse. Immunization with VP254 was not protective. In guinea pigs VP221 did not protect against primary HSV-2 cutaneous disease but did reduce the proportion of animals with recurrent disease (P less than .05). This partial protection appears to be associated with the role of type-specific antigenic determinants in gD-2 immunoregulation.

Animals↗
PubMed2005

Stress as an endogenous adjuvant: augmentation of the immunization phase of cell-mediated immunity.

Stress is thought to be immunosuppressive but paradoxically exacerbates inflammatory and autoimmune diseases. We initially showed that acute stress enhances skin immunity. Such immunoenhancement could promote immunoprotection in case of wounding, infection or vaccination but could also exacerbate immunopathological diseases. Here we identify the molecular and cellular mediators of the immunoenhancing effects of acute stress. Compared with non-stressed mice, acutely stressed animals showed significantly greater pinna swelling and leukocyte infiltration, and up-regulated macrophage chemoattractant protein-1, macrophage inflammatory protein-3alpha, IL-1alpha, IL-1beta, IL-6, tumor necrosis factor-alpha and IFN-gamma, but not IL-4 gene expression at the site of primary antigen exposure. Stressed animals also showed enhanced maturation and trafficking of dendritic cells (DCs) from skin to lymph nodes (LNs), higher numbers of activated macrophages in skin and LNs, increased T cell activation in LNs, and enhanced recruitment of surveillance T cells to skin. These findings show that important interactive components of innate (DCs and macrophages) and adaptive (surveillance T cells) immunity are mediators of the stress-induced enhancement of a primary immune response. Such enhancement during primary immunization may induce a long-term increase in immunologic memory resulting in subsequent augmentation of the immune response during secondary antigen exposure. Thus, the evolutionarily adaptive fight-or-flight stress response may protectively prepare the immune system for impending danger (e.g. infection and wounding by a predator), but may also contribute to stress-induced exacerbation of inflammatory and autoimmune diseases.

Animals↗
PubMed1997

Effect of therapeutic immunization with recombinant gp160 HIV-1 vaccine on HIV-1 proviral DNA and plasma RNA: relationship to cellular immune responses.

Therapeutic vaccination has been proposed as a strategy to augment immune mechanisms to control viral replication and slow clinical progression of HIV infection to disease. Following recombinant gp160 (r-gp160) immunization in three clinical trials, plasma HIV-1 RNA and cellular proviral DNA were assessed by quantitative polymerase chain reaction (PCR) in 76 HIV-seropositive subjects with CD4+ T cell counts > or = 300/mm3. Immunization increased HIV-specific cellular immune responses (e.g., cytotoxic T lymphocyte [CTL] activities, lymphocyte proliferative responses); however, there were no significant effects of immunization or cellular immune responses on measures of plasma RNA or cellular DNA viral load.

AIDS Vaccines↗
PubMed1994

Neonatal infection of mice with lactate dehydrogenase-elevating virus results in suppression of humoral antiviral immune response but does not alter the course of viraemia or the polyclonal activation of B cells and immune complex formation.

Neonatal infection of FVB mice with lactate dehydrogenase-elevating virus (LDV) prevented the normal formation of anti-LDV antibodies observed in mice infected at 5 days of age or older. Even 22 weeks post-infection, the concentration of circulating anti-LDV antibodies in neonatally infected mice was insignificant. However, the time course and level of persistent viraemia were the same in neonatally infected mice lacking anti-LDV antibodies as in mice infected at 5 or 15 days of age which developed normal antiviral immune responses. The results support the view that LDV replication in mice is unaffected by antiviral immune responses and instead is primarily dependent on the rate of regeneration of LDV-permissive macrophages. This view is further supported by the following findings. Treatment of mice with cyclophosphamide or dexamethasone, which are known to increase plasma LDV levels, increased the proportion of LDV-permissive macrophages in the peritoneum. Injection of mice with interleukin-3, which is known to stimulate macrophage development, increased plasma LDV levels in persistently infected mice 10- to 100-fold. During the first month of age when mice possess a higher proportion of LDV-permissive macrophages than older mice and peritoneal macrophages exhibit self-sustained growth, the persistent plasma LDV titres were also 10- to 100-fold higher than in older mice. The polyclonal activation of B cells induced by LDV that results in a permanent elevation of IgG2a or IgG2b in the circulation, and the formation of 180K to 300K immune complexes containing IgG2a or IgG2b were also the same in neonatally infected mice and mice infected 5 or 15 days after birth. Thus, the polyclonal activation of B cells occurs in the absence of an antiviral humoral immune response and the immune complexes do not contain anti-LDV antibodies. The immune complexes probably consist of autoantibodies formed in the course of the polyclonal activation of B cells and their cellular antigens.

Animals↗
PubMed1992

Transfer of specific immunity from donor to recipient of an allogeneic bone marrow graft: effect of conditioning on the specific immune response of the graft recipient.

Transfer of specific immunity was investigated in a group of 28 paediatric and adult leukaemia patients during the first 100 d after allogeneic bone marrow transplantation (BMT). These patients and/or their donors were immunized 7-13 d before transplantation with the recall antigen tetanus toxoid (TT) and the neo-antigen Helix pomatia haemocyanin (HPH). The recipients were booster immunized with both antigens at day 42 after transplantation. Transfer of a primary IgM and IgG response to HPH was successful in most paediatric and adult patients, but transfer of a secondary response to TT was established in only a few paediatric recipients. After booster immunization at day 42 most paediatric recipients responded with a rise in serum antibody titre to HPH as opposed to only two of 18 adult recipients. This incapability of the adult recipients to mount a secondary immune response may be related to their conditioning regimen which included Campath-IG in vivo. The results from this study indicate that transfer of immunity against recall- and neo-antigens is possible. However, the establishment of long-term memory may be affected by the regimen used to condition the graft recipient.

Adolescent↗
PubMed1981

The response of mice immune to Schistosoma mansoni to a challenge infection which bypasses the skin: evidence for two mechanisms of immunity.

Mice which had developed immunity to reinfection with Schistosoma mansoni following exposure to 20 cercariae and mice which had been immunized against S. mansoni by exposure to 400 highly irradiated (20 krad) cercariae, were tested for their ability to resist a percutaneous cercarial challenge and an intravenous challenge with 5-day-old lung-stage schistosomula derived from the same cercariae. Although both types of immune mice showed a marked resistance to a cercarial challenge, only the infected mice showed a comparable immunity to an intravenous challenge with lung schistosomula. These results confirm earlier studies which suggest that the major attrition of a cercarial challenge in infected mice occurs at the post-lung stage, whilst the attrition of a challenge infection in mice immunized with highly irradiated cercariae takes place in the skin. They provide further evidence for two separate mechanisms of immunity against S. mansoni in mice.

Animals↗
PubMed1985

Antibody response against schistosomulum surface antigens and protective immunity following immunization with highly irradiated cercariae of Schistosoma mansoni.

The production of antibodies against the schistosomulum surface antigens of Schistosoma mansoni in response to immunization with highly irradiated cercariae was followed. Four antigens were reproducibly identified by 125I surface labelling using Iodogen and immunoprecipitation; they had mol. wts of 38, 32, 20 and 15 kD. In addition a 92 kD antigen was also evident in most experiments. It was demonstrated that the 20 kD antigen was the same as that recognized by the monoclonal antibody NIMP/M.47 and that this antigen like the 38 and 32 kD antigens was thus identified during both chronic infection and following vaccination with irradiated cercariae. Two weeks following immunization with irradiated cercariae antibody was produced only against the 15 kD antigen but at 4 weeks the major response was against the 32 kD antigen. A second immunization with irradiated cercariae boosts the antibody response so that all four antigens were strongly precipitated. Further vaccinations did not lead to the identification of further antigens. Immunization of rats with highly irradiated cercariae also resulted in antibody production against the 38, 32, 20 and 15 kD antigens. Surface labelling of schistosomula transformed from irradiated cercariae resulted in the same four antigens being precipitated as from normal cercariae indicating that irradiation did not affect transformation nor antigen expression on 3h schistosomula. Furthermore, antibodies against the same surface antigens were detectable 4 weeks after immunization with equal numbers of cercariae irradiated with 0, 5, 25 or 50 krad. Vaccination of mice with irradiated, cloned cercariae resulted in identical antibody production and similar levels of immunity directed at both an homologous or heterogeneous challenge. Thus all parasites within our laboratory population appear to express the same antigens and there was no evidence for a genetically defined variation that could account for the partial resistance to reinfection exhibited by mice vaccinated with irradiated cercariae.

Animals↗
PubMed1988

Lacteal immunity to enteric cryptosporidiosis in mice: immune dams do not protect their suckling pups.

The susceptibilities of passively immunized principal and nonimmunized control suckling mice to orogastric challenge with Cryptosporidium parvum oocysts were compared. Principals were suckled by dams that had recovered from C. parvum infection. Controls were suckled by dams reared free of C. parvum infection. Principals and controls were equally susceptible to challenge. Principals were susceptible even when their dams were hyperimmunized by oral and parenteral booster inoculations with C. parvum oocysts. Immune dams produced serum antibody against C. parvum, while nonimmune dams did not. Anti-cryptosporidia immunoglobulin G (IgG) and IgA were demonstrated in whey extracted from the stomachs of principals that had suckled immune dams but not in whey extracted from the stomachs of controls. It was concluded that passive lacteal immunity is not an efficient means of protection against cryptosporidiosis in mice. As in other coccidian infections, protective immunity against cryptosporidiosis may depend more on immune cells than on antibody.

Animals↗
PubMed2005

Coccidiosis immunization: effects of mushroom and herb polysaccharides on immune responses of chickens infected with Eimeria tenella.

An experiment was conducted to investigate the effects of polysaccharide extracts (E) of two mushrooms, Lentinus edodes (LenE) and Tremella fuciformis (TreE), and an herb, Astragalus membranaceus (AstE), on the immune responses of chickens infected with Eimeria tenella. A total of 180 broiler chickens were assigned to nine groups: three groups were fed with each of the extracts (LenE, TreE, and AstE), three groups were fed with the extracts and immunized with live oocyst vaccine (LenE+V, TreE+V, and AstE+V), a group was immunized with the vaccine only, and there were two controls (E. tenella-infected and noninfected groups). The oocyst vaccine was given at 4 days of age, and the extracts (1 g/kg of the diet) were supplemented from 8 to 14 days of age. At 18 days of age, all birds except those in the noninfected group were infected with 9 x 10(4) sporulated oocysts. The results showed that at 7 days postinfection (p.i.), birds fed the extracts without vaccination had lower body weight (BW) gain than those given the vaccine only. However, the extracts in conjunction with the vaccine significantly enhanced BW gain of the infected chickens compared with the vaccine group. Of the three extracts, LenE and TreE showed a better growth-promoting effect. The extracts largely increased oocyst excretion of droppings during the primary response postvaccination. The cecal peak oocyst output and lesion scores measured at 7 days p.i. were higher in the groups fed the extracts than in the group immunized with the vaccine only, whereas those of the groups fed with the extracts and immunized with the vaccine were not significantly different from the vaccine group. Of the three extracts, both LenE- and AstE-fed groups showed lower cecal oocyst output. Thus, as compared with the extracts, the live, attenuated vaccine showed better results with significantly increased immune response in coccidial infected birds. The polysaccharide extracts may prove useful against avian coccidiosis, and, particularly when they are used in conjunction with vaccine, they have shown preliminary promise against the experimental coccidial infection.

Agaricales↗
PubMed2005

Induction of anti-chlamydial mucosal immunity by transcutaneous immunization is enhanced by topical application of GM-CSF.

Transcutaneous immunization (TCI) involves the direct application of antigen plus adjuvant to skin, taking advantage of the large numbers of Langerhans cells and other resident skin dendritic cells, that process antigen then migrate to draining lymph nodes where immune responses are initiated. We have used this form of immunization to protect mice against genital tract and respiratory tract chlamydial infection. Protection was associated with local antibody responses in the vagina, uterus and lung as well as strong Th1 responses in the lymph nodes draining the reproductive tract and lungs respectively. In this study we show that topical application of GM-CSF to skin enhances the numbers and activation status of epidermal dendritic cells. Topical application of GM-CSF also increased the immune responses elicited by TCI. GM-CSF supplementation greatly increased cytokine (IFNgamma and IL-4) gene expression in lymph node and splenic cells compared to cells from animals immunized without GM-CSF. IgG responses in serum, uterine lavage and bronchoalveolar lavage and IgA responses in vaginal lavage were also increased by topical application of GM-CSF. The studies show that TCI induces protection against genital and respiratory tract chlamydial infections and that topical application of cytokines such as GM-CSF can enhance TCI-induced antibody and cell-mediated immunity.

Administration, Cutaneous↗
PubMed2004

Protective immunity in rainbow trout Oncorhynchus mykiss following immunization with distinct molecular mass fractions isolated from Flavobacterium psychrophilum.

Vaccine development for coldwater disease (CWD), also known as rainbow trout fry syndrome (RTFS), has been based primarily on whole-cell bacterins or outer membrane fractions of Flavobacterium psychrophilum. In the present study, immunogenic regions of the bacterium corresponding to 18-28, 41-49, and 70-100 kDa were identified by western blot analysis using rainbow trout Oncorhynchus mykiss immune sera. Following sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), antigens within these regions were isolated by electro-elution and used in immunization trials. Groups of rainbow trout fry were immunized with these regions emulsified with Freund's complete adjuvant (FCA) and a formalin-killed bacterin emulsified with FCA. It was demonstrated that the 70-100 and 41-49 kDa regions and F. psychrophilum treatments elicited significant protection when compared to the saline control following subcutaneous challenge with 2 doses of a virulent strain of F. psychrophilum. Immunization with the 70-100 kDa region resulted in near complete protection in fish with mean cumulative percent mortality (CPM) of 6% and mean relative percent survival (RPS) of 94% at the lower challenge dose (6.25 x 10(6) colony forming units fish(-1)). This preparation also stimulated a high level of specific antibody to F. psychrophilum, as detected by an enzyme-linked immunosorbent assay (ELISA). Western blot analysis using sera from fish immunized with the 70-100 kDa region demonstrated that high molecular weight proteins and the O-polysaccharide component of lipopolysaccharide (LPS) are recognized by serum antibodies. This suggests that these antigens may be involved in eliciting a highly protective immune response, and could serve as vaccine candidates.

Analysis of Variance↗
PubMed2002

Immune responses to small nuclear ribonucleoproteins: antigen-dependent distinct B cell epitope spreading patterns in mice immunized with recombinant polypeptides of small nuclear ribonucleoproteins.

Complex patterns of autoantibody reactivities with the small nuclear ribonucleoproteins (snRNPs) are observed in systemic lupus erythematosus. To investigate the role of individual snRNP components in the initiation and diversification of anti-snRNP Ab responses, we immunized A/J mice with recombinant Smith D (SmD), Smith B (SmB), and A ribonucleoprotein (A-RNP) with alum as adjuvant. Sera at different time points after initial immunizations were analyzed by Western blot and immunoprecipitation assays. In SmD-immunized mice, specific Abs to A-RNP and SmB were generated by 2 mo postimmunization, in addition to the detection of cross-reactive Abs between the immunogen and other snRNPs. Whereas Abs reactive with the immunogen decreased by 5 mo, Abs capable of immunoprecipitating A-RNP and SmB increased. In SmB-immunized mice, specific Abs to A-RNP were readily detectable, in addition to cross-reactive Abs. In contrast, A-RNP-immunized mice had only cross-reactive Abs to SmB without detectable Abs to SmD. However, in these mice, specific Abs to the 70-kDa protein were generated. Abs, which precipitated the native snRNP particle, were generated in all three groups of the immunized mice. Our results show that different initiating Ags from the same multiprotein antigenic complex induce distinct patterns of epitope spreading to proteins within that complex. These data have significant implications for the mechanisms of autoantibody diversification in systemic lupus erythematosus.

Animals↗
PubMed1992

The role of IgG antibodies from irradiated cercaria-immunized rabbits in the passive transfer of immunity to Schistosoma mansoni-infected mice.

Antibodies of the IgG subclass isolated from the sera of rabbits immunized with cercariae subjected to 50 kilorads of gamma irradiation passively provided partial immunity against Schistosoma mansoni challenge in C57B1/6J mice. These mice exhibited reductions in adult worm burdens of 43-61% compared with recipients of normal rabbit antibodies. Passively transferred IgG antibodies were most effective when given 4-7-days postchallenge; they were less effective when given just before challenge, and were totally ineffective when given 15 days postchallenge. It was also shown that the Fc portion of the IgG molecule was important for passive transfer of immunity. Finally, we observed that although some antibodies from irradiated cercaria-immunized rabbits recognized keyhole limpet hemocyanin (KLH), these KLH cross-reacting antibodies were not necessary for successful passive transfer of immunity. Antibodies from a KLH-immunized rabbit also failed to passively protect mice.

Animals↗
PubMed1999

Absolute requirement for an active immune response involving B cells and Th cells in immunity to Plasmodium yoelii passively acquired with antibodies to the 19-kDa carboxyl-terminal fragment of merozoite surface protein-1.

Vaccination of mice with the leading malaria vaccine candidate homologue, the 19-kDa carboxyl terminus of merozoite surface protein-1 (MSP119), results in sterile immunity to Plasmodium yoelii, with no parasites detected in blood. Although such immunity depends upon high titer Abs at challenge, high doses of immune sera transferred into naive mice reduce parasitemia (and protect from death) but do not result in a similar degree of protection (with most mice experiencing high peak parasitemias); this finding suggests that ongoing parasite-specific immune responses postchallenge are essential. We analyzed this postchallenge response by transferring Abs into manipulated but malaria-naive mice and observed that Abs cannot protect SCID, nude, CD4+ T cell-depleted, or B cell knockout mice, with all mice dying. Thus, in addition to the Abs that develop following MSP119 vaccination, a continuing active immune response postchallenge is required for protection. MSP119-specific Abs can adoptively transfer protection to strains of mice that are not protected following vaccination with MSP119, suggesting that the Ags targeted by the immune response postchallenge include Ags apart from MSP119. These data have important implications for the development of a human malaria vaccine.

Animals↗
PubMed2000

Delayed-type hypersensitivity response is a predictor of peripheral blood T-cell immunity after HER-2/neu peptide immunization.

Many groups that immunize cancer patients with cancer vaccines use the generation of a delayed-type hypersensitivity (DTH) response as the primary measure of the ability to immunize a patient to a tumor cell or specific tumor antigen. This study examines whether the development of a tumor antigen-specific DTH response, measured after vaccination with peptide-based vaccines, correlates to in vitro assessment of peripheral blood antigen-specific T-cell responses. The HER-2/neu protein was used as a model tumor antigen. Thirty-two patients who completed a course of immunization with HER-2/neu peptide-based vaccines were analyzed. HER-2/neu peptide-specific DTH responses (n = 93) and peripheral blood T-cell responses (n = 93) were measured 30 days after the final immunization. Size of DTH induration was correlated with HER-2/neu-specific T-cell proliferative responses assessed from peripheral blood lymphocytes isolated concurrently with peptide skin test placement. HER-2/neu peptide-specific DTH responses > or =10 mm2 correlated significantly to a measurable peptide-specific peripheral blood T-cell response defined as stimulation index >2.0 (P = 0.0006). However, antigen-specific DTH responses with magnitudes between 5 and 9 mm2 were not significantly associated with the development of systemic immunity. DTH responses between 5 and 9 mm2 carried an odds ratio of 1.3 (P = 0.61) in predicting a measurable systemic tumor antigen response. The findings presented here demonstrate that tumor antigen-specific DTH responses > or =10 mm2 correlate with measurable in vitro antigen-specific lymphocytic proliferation and are, in this model system, a reflection of systemic immunization.

Breast Neoplasms↗
PubMed1976

[Immunity against Erysipelothrix rhusiopathiae infection by means of active immunization using homologous neuraminidase (author's transl)].

Neuraminidase may play a role as a pathogenic factor in Erysipelothrix rhusiopathiae infection. The protective effect of active immunization with purified neuraminidase was therefore tested in an infection experiment in white mice. Mice were immunized 2, 4, 6, 8 or 10 times i.p. with Erysipelothrix neuraminidase. A control group received 10 injections with physiological saline. The infective dose varied between 7 and 7 x 10(7) cells. While all control animals infected with 7 x 10(1) germs died, the lethal effect could be reduced to 50% and 25% in animals immunized twice and 4 times, respectively. Only animals immunized 8 and 10 times were still partly protected against germ numbers of 10(3)-10(4). Germ numbers of 10(5) and more were almost always fatal even in highly immunized animals. Even a high immunization with neuraminidase could only lower the lethal by a maximum factor of 10(4) germs used.

Animals↗
PubMed2005

Effects of extra immunization efforts on routine immunization at district level in Pakistan.

A study was made of the effects of extra immunization activities on routine immunization coverage at district level in Pakistan in a secondary analysis of data from UNICEF and the Pakistan national census. Linear regression analysis was made on data from 107 districts to estimate the effects of extra immunization efforts in the national neonatal tetanus programme on the coverage rate of the third dose of diphtheria-pertussis-tetanus (DPT3) after controlling for other potential confounding factors. The districts that implemented extra national neonatal tetanus immunization were at risk of having lower routine DPT3 coverage than those that did not. Additional immunization efforts, without additional resources, may reduce the effect of the routine Expanded Programme on Immunization.

Cluster Analysis↗