Immunogenicity, reactogenicity, and IgE-mediated immune responses of a mixed whole-cell and acellular pertussis vaccine schedule in Australian infants: A randomised, double-blind, noninferiority trial.

BACKGROUND: In many countries, infant vaccination with acellular pertussis (aP) vaccines has replaced use of more reactogenic whole-cell pertussis (wP) vaccines. Based on immunological and epidemiological evidence, we hypothesised that substituting the first aP dose in the routine vaccination schedule with wP vaccine might protect against IgE-mediated food allergy. We aimed to compare reactogenicity, immunogenicity, and IgE-mediated responses of a mixed wP/aP primary schedule versus the standard aP-only schedule. METHODS AND FINDINGS: OPTIMUM is a Bayesian, 2-stage, double-blind, randomised trial. In stage one, infants were assigned (1:1) to either a first dose of a pentavalent wP combination vaccine (DTwP-Hib-HepB, Pentabio PT Bio Farma, Indonesia) or a hexavalent aP vaccine (DTaP-Hib-HepB-IPV, Infanrix hexa, GlaxoSmithKline, Australia) at approximately 6 weeks old. Subsequently, all infants received the hexavalent aP vaccine at 4 and 6 months old as well as an aP vaccine at 18 months old (DTaP-IPV, Infanrix-IPV, GlaxoSmithKline, Australia). Stage two is ongoing and follows the above randomisation strategy and vaccination schedule. Ahead of ascertainment of the primary clinical outcome of allergist-confirmed IgE-mediated food allergy by 12 months old, here we present the results of secondary immunogenicity, reactogenicity, tetanus toxoid IgE-mediated immune responses, and parental acceptability endpoints. Serum IgG responses to diphtheria, tetanus, and pertussis antigens were measured using a multiplex fluorescent bead-based immunoassay; total and specific IgE were measured in plasma by means of the ImmunoCAP assay (Thermo Fisher Scientific). The immunogenicity of the mixed schedule was defined as being noninferior to that of the aP-only schedule using a noninferiority margin of 2/3 on the ratio of the geometric mean concentrations (GMR) of pertussis toxin (PT)-IgG 1 month after the 6-month aP. Solicited adverse reactions were summarised by study arm and included all children who received the first dose of either wP or aP. Parental acceptance was assessed using a 5-point Likert scale. The primary analyses were based on intention-to-treat (ITT); secondary per-protocol (PP) analyses were also performed. The trial is registered with ANZCTR (ACTRN12617000065392p). Between March 7, 2018 and January 13, 2020, 150 infants were randomised (75 per arm). PT-IgG responses of the mixed schedule were noninferior to the aP-only schedule at approximately 1 month after the 6-month aP dose [GMR = 0·98, 95% credible interval (0·77 to 1·26); probability (GMR > 2/3) > 0·99; ITT analysis]. At 7 months old, the posterior median probability of quantitation for tetanus toxoid IgE was 0·22 (95% credible interval 0·12 to 0·34) in both the mixed schedule group and in the aP-only group. Despite exclusions, the results were consistent in the PP analysis. At 6 weeks old, irritability was the most common systemic solicited reaction reported in wP (65 [88%] of 74) versus aP (59 [82%] of 72) vaccinees. At the same age, severe systemic reactions were reported among 14 (19%) of 74 infants after wP and 8 (11%) of 72 infants after aP. There were 7 SAEs among 5 participants within the first 6 months of follow-up; on blinded assessment, none were deemed to be related to the study vaccines. Parental acceptance of mixed and aP-only schedules was high (71 [97%] of 73 versus 69 [96%] of 72 would agree to have the same schedule again). CONCLUSIONS: Compared to the aP-only schedule, the mixed schedule evoked noninferior PT-IgG responses, was associated with more severe reactions, but was well accepted by parents. Tetanus toxoid IgE responses did not differ across the study groups. TRIAL REGISTRATION: Trial registered at the Australian and New Zealand Clinical 207 Trial Registry (ACTRN12617000065392p).

Postmarketing Safety Surveillance of a Hexavalent Vaccine in the Vaccine Adverse Event Reporting System.

We assessed the safety of hexavalent vaccine diphtheria and tetanus toxoids and acellular pertussis, inactivated poliovirus, hepatitis b, and haemophilus influenzae b conjugate vaccine in the Vaccine Adverse Event Reporting System. Five hundred-one reports of adverse events (AEs) were identified; 21 (4.2%) were serious. Most frequently reported AEs were fever (10.2%) and injection site erythema (5.4%). AEs reported were consistent with findings from prelicensure studies.

Gene expression profiling reveals insights into infant immunological and febrile responses to group B meningococcal vaccine.

Neisseria meningitidis is a major cause of meningitis and septicaemia. A MenB vaccine (4CMenB) was licensed by the European Medicines Agency in January 2013. Here we describe the blood transcriptome and proteome following infant immunisations with or without concomitant 4CMenB, to gain insight into the molecular mechanisms underlying post-vaccination reactogenicity and immunogenicity. Infants were randomised to receive control immunisations (PCV13 and DTaP-IPV-Hib) with or without 4CMenB at 2 and 4 months of age. Blood gene expression and plasma proteins were measured prior to, then 4 h, 24 h, 3 days or 7 days post-vaccination. 4CMenB vaccination was associated with increased expression of ENTPD7 and increased concentrations of 4 plasma proteins: CRP, G-CSF, IL-1RA and IL-6. Post-vaccination fever was associated with increased expression of SELL, involved in neutrophil recruitment. A murine model dissecting the vaccine components found the concomitant regimen to be associated with increased gene perturbation compared with 4CMenB vaccine alone with enhancement of pathways such as interleukin-3, -5 and GM-CSF signalling. Finally, we present transcriptomic profiles predictive of immunological and febrile responses following 4CMenB vaccine.

Immunogenicity and safety of a DTaP-IPV/Hib pentavalent vaccine given as primary and booster vaccinations in healthy infants and toddlers in Japan.

BACKGROUND: Globally, the use of single DTaP-IPV/Hib vaccines that combine DTaP-IPV and Hib is widespread, but in Japan vaccination is usually concomitant at separate sites. The immunogenicity and safety of a primary vaccination series and booster of a combined pentavalent DTaP-IPV/Hib vaccine were evaluated and compared to separate administration of DTaP-IPV and Hib in Japanese infants. METHODS: Healthy Japanese infants were administered DTaP-IPV/Hib (Group A: N = 207) or DTaP-IPV + Hib (Group B: N = 207) by the subcutaneous (SC) or DTaP-IPV/Hib by the intramuscular (IM) route (Group C: N = 10). All subjects received a 3-dose primary vaccination series and a booster. Non-inferiority (Group A versus Group B) was tested post-primary series and subsequent post hoc analyses were performed for anti-Hib. Safety was assessed by parental reports. RESULTS: Non-inferiority for SC administration of Group A versus Group B for the primary series was demonstrated for antibody responses to all antigens except Hib using the threshold of 1.0 µg/mL. Post hoc analyses for anti-Hib demonstrated non-inferiority for the primary series response using 0.15 µg/mL, and for pre-booster antibody persistence and the booster response using 0.15 µg/mL and 1.0 µg/mL. The immune response was similar for each antigen following SC or IM administration. There were no safety concerns in any group, and a lower incidence of injection sites for the IM route was observed as expected. CONCLUSIONS: These data show the good immunogenicity and safety profile of the DTaP-IPV/Hib vaccine as a 3-dose infant primary series followed by a booster in the second year of life in Japan.

Infantile bullous pemphigoid successfully treated with combined pulse corticosteroids and high-dose IVIG.

Bullous pemphigoid is the most common autoimmune blistering disorder in the elderly. It affects people aged 70 years or older. Clinically it is characterized by intensely pruritic eruption consisting of widespread tense blisters on an erythematous background. It is associated with cellular and humoral responses against hemidesmosomal components of the skin and mucous membranes. In contrast, infantile bullous pemphigoid is exceedingly rare disease and presents with some unique features like favorable prognosis, possible association with vaccination, and primary involvement of acral surfaces. Herein, we present a case of 4,5-month-old infant with neonatal pemphigoid, successfully treated with a combination of intravenous immunoglobulins and pulse methylprednisolone.

DTwP-HB-Hib: antibody persistence after a primary series, immune response and safety after a booster dose in children 18-24 months old.

BACKGROUND: The new combination of DTwP-HB-Hib vaccines has been developed in Indonesia following World Health Organization (WHO) recommendation and integrated into national immunization program. The aims of the study were to measure 1) antibody persistence 12-18 months after a primary series, 2) immune response and safety after a booster dose of DTwP-HB-Hib. METHODS: This was a multi-center, open-labeled, prospective, interventional study. Subjects who had received complete primary dose of DTwP-HB-Hib vaccine from the previous phase III trial were recruited in this trial. Subjects were given one dose of DTwP-HB-Hib (Pentabio®) booster at age 18-24 months old. Diphtheria, tetanus, pertussis, hepatitis B, Hemophilus influenza type B antibodies were measured before and after booster to determine antibody persistence and immune response. Vaccine adverse events were assessed immediately and monitored until 28 days after the booster recorded with parent's diary cards. RESULTS: There were 396 subjects who completed the study. Increased proportion of seroprotected subjects from pre-booster to post-booster were noted in all vaccine antigens: 74.5 to 99.7% for diphtheria; 100 to 100% for tetanus; 40.4 to 95.5% for pertussis; 90.2 to 99.5% for hepatitis B; and 97.7 to 100% for Hib. Common systemic adverse events (AEs) were irritability (23.7-25%) and fever (39.9-45.2%). Local AEs such as redness, swelling, and induration were significantly less common in the thigh group (7.7, 11.3, and 7.1%) than in the deltoid group (28.9, 30.7, and 25%) (P < 0.001). Most AEs were mild and resolved spontaneously within three-day follow-up period. CONCLUSIONS: Booster of DTwP-HB-Hib vaccine at age 18-24 months is required to achieve and maintain optimal protective antibody. The vaccine is safe and immunogenic to be used for booster vaccination. TRIAL REGISTRATION: NCT02095314 (retrospectively registered, March 24, 2014).

Atypical aluminium patch tests in children with persistent itching postvaccinal nodules.

Persistent itching nodules related to aluminium-adsorbed vaccines are well known in children with frequent positive patch tests to aluminium when tested. We report two cases of children with persistent postvaccination nodules who presented with atypical eruptions after aluminium patch tests.

Vaccine-induced immune thrombocytopaenia purpura in autologous haematopoietic stem cell transplantation.

Immune Thrombocytopenia Purpura (ITP) secondary to vaccinations is rare, especially after autologous hematopoietic stem cell transplantation (HSCT). A 31-yearold female received autologous HSCT for relapsed Hodgkin Disease, with platelet engraftment at Day+14. One week after receiving second scheduled vaccinations, she developed severe thrombocytopenia (3x109/L) associated with pharyngeal hematoma. Bone marrow (BM) examinations were consistent with ITP, possibly secondary to Influenza vaccine. Platelet increment was poor despite high dose corticosteroids, intravenous immunoglobulin (IVIG), Danazol and Eltrombopag. A repeated BM biopsy was in agreement with ITP. Re-treatment with tapering doses of prednisolone resulted in stable platelet counts at 120x109/L a year later.

Adverse events following immunization with pentavalent vaccine: experiences of newly introduced vaccine in Iran.

BACKGROUND: The most important factors that affect the incidence of vaccine-related complications are the constituent biological components of the vaccine, injection site reactions, age and sex. The aim of this study is to determine the incidence rate of adverse events following immunization with pentavalent vaccine (DTPw-Hep B-Hib (PRP-T) vaccine (pentavac) (adsorbed) is manufactured by Serum Institute of India ltd), which was introduced in Iran in November 2014. It is important to monitor vaccine-related adverse events because of the role of vaccine safety in immunization program success. METHODS: This study was a mixed cohort study that included 1119 children less than 1 year of age. In 2015, the children were referred to Hamadan health centers to receive pentavalent vaccine at 2, 4 and 6 months of age. The data were collected from the parents of the children using a questionnaire that was administered either face-to-face or by telephone. The cumulative incidence of side effects and risk ratio was reported with 95% confidence intervals (CI). Chi-squared tests and logistic regressions were used to investigate the association between the variables. RESULTS: The cumulative incidence rate of pentavalent-related adverse events during 48 h following immunization was estimated to be 15.8% for swelling, 10.9% for redness, 44.2% for pain, 12.6% for mild fever, 0.1% for high fever, 20.0% for drowsiness, 15.0% for loss of appetite, 32.9% for irritability, 4.6% for vomiting and 5.5% for persistent crying. There is no evidence for the occurrence of convulsion and encephalopathy among children who receive pentavalent vaccines. CONCLUSION: Further large studies with long time follow up are required to address rare events include convulsions, encephalopathy or persistent crying. However, Findings urge immunization programs to use pentavalent vaccinations and to continue implementing the current immunization program in children under 1 year of age.

Comparison of the tolerability of newly introduced childhood vaccines in the Netherlands.

In 2011, the 7-valent conjugated pneumococcal vaccine (PCV7) was replaced by the 10-valent vaccine (PCV10) and universal hepatitis B vaccination has been introduced in the Netherlands. A questionnaire study was conducted to assess the tolerability of DTaP-IPV-Hib + PCV7 (PCV7-cohort), DTaP-IPV-Hib + PCV10 (PCV10-cohort), and DTaP-IPV-Hib-HepB + PCV10 (HepB-cohort). Parents were asked to report in questionnaires local reactions and systemic adverse events (AEs) before and after vaccination of their infant at 2, 3, 4, and 11 months of age. For 29.0 and 29.4% infants of the PCV7-cohort, at least one local reaction was reported in the week after the first dose of DTaP-IPV (left leg) and PCV-7 vaccination (right leg). Significantly more infants from the PCV10-cohort (45.1%, p < 0.001 and 44.6%, p < 0.001) and HepB-cohort (42.6%, p < 0.001 and 41.9%, p < 0.001) reported at least one local reaction. This effect was less pronounced after the successive doses. Most of the infants experienced at least one systemic AE, and after dose 4, this was higher for infants in the PCV10-cohort (65.9%, p = 0.047) and HepB-cohort (70.6%, p = 0.000) compared to the PCV7-cohort (62.3%). CONCLUSION: Addition of antigens to a vaccine resulted in a higher reactogenicity, but the AEs were in general mild and transient. What is Known: • Assessment of adverse events is crucial for achieving the highest safety in immunization programs, in order to inform public health actions and maintain public confidence in immunization programs. What is New: • Newly introduced vaccines DTaP-IPV-Hib-HepB and PCV10 are generally safe and well tolerated in infants. • These results are useful for information purposes and for monitoring variations in rates of AEs in the general population or in the target group over time.

Prophylactic antipyretics for prevention of febrile seizures following vaccination.

Question Parents of a 12-month-old boy are bringing their son in to my family practice clinic for his well-baby visit. As the infant is due for his 12-month vaccine series, the parents are concerned after hearing about the association between certain vaccinations and an increased risk of febrile seizures, and are wondering if they should administer prophylactic antipyretics to decrease the risk of febrile seizure. What vaccinations are associated with increased risk of febrile seizure, and is there evidence supporting prophylactic administration of antipyretics to prevent febrile seizures? Answer Vaccinations associated with increased risk of febrile seizure include the following: the measles-mumps-rubella vaccine; the measles-mumps-rubella-varicella vaccine; the combined diphtheria, tetanus, acellular pertussis, polio, and Haemophilus influenzae type b vaccine; the whole-cell pertussis vaccine; the 7-valent pneumococcal conjugate vaccine; and concomitant administration of the trivalent inactivated influenza vaccine with either the 7-valent pneumococcal conjugate vaccine or the diphtheria, tetanus, and acellular pertussis vaccine. Despite being a higher-risk group, children receiving these vaccinations should not receive prophylactic antipyretics, as no statistically significant reduction in the rate of febrile seizures has been documented, and prophylactic antipyretic use potentially decreases the immune response to certain vaccines.

[Hypotonic-Hyporesponsive Episode after immunization with whole-cell pertussis combination vaccine. Clinical Case Report]. / Episodio Hipotonía-Hiporreactividad posterior a la inmunización con vacuna combinada con pertussis de células enteras. Reporte de un caso.

INTRODUCTION: Hypotonic-Hyporesponsive Episode (HHE) is an adverse event after vaccination, mainly associated with whole-cell pertussis vaccines. It is characterized by a sudden onset of muscle flaccidity, reduced response to stimuli and pallor or cyanosis. Although the HHE is infrequent, it is considered a severe adverse event. OBJECTIVE: To report a case of HHE following the administration of the whole-cell pertussis combination vaccine (DTwP-HB-Hib), which is included in National Im munization Program (PNI) of Chile, and to contributing to the knowledge of this adverse event in the country. CASE REPORT: A 6-month-old infant, 3 hours post-vaccination with the third dose of DTwP-HB-Hib vaccine, presented a decreased level of consciousness that was interpreted as atonic seizure but finally considered as EHH. The infant progressed favorably after 2 hours of clinical observation and was discharged 24 hours later. Parents were suggested to continue the immunization schedule of the infant with acellular pertussis vaccines as a preventive measure. CONCLUSIONS: The lack of knowledge about the EHH may discourage childhood immunization. Therefore, it is important for the medical staff to inform parents of the patients about this benign, self-limited and non-recurrent adverse event. In these cases, it is recommended to continue the immunization schedule of the infant with acellular pertussis vaccines.

Food and Drug Administration Approval for Use of Hiberix as a 3-Dose Primary Haemophilus influenzae Type b (Hib) Vaccination Series.

On January 14, 2016, GlaxoSmithKline Biologicals (Research Triangle Park, North Carolina) received approval from the Food and Drug Administration (FDA) to expand use of Hiberix (Haemophilus b Conjugate Vaccine [Tetanus Toxoid Conjugate]) for a 3-dose infant primary vaccination series at ages 2, 4, and 6 months. Hiberix was first licensed in the United States in August 2009 for use as a booster dose in children aged 15 months through 4 years under the Accelerated Approval Regulations, in response to a Haemophilus influenzae type b (Hib) vaccine shortage that lasted from December 2007 to July 2009 (1). Expanding the age indication to include infants provides another vaccine option in addition to other currently licensed monovalent or combination Hib vaccines recommended for the primary vaccination series.* Hiberix contains 10 µg purified capsular polyribosyl ribitolphosphate (PRP) conjugated to 25 µg tetanus toxoid (PRP-T) and is supplied as a single-dose vial of lyophilized vaccine to be reconstituted with saline diluent. For the 3-dose primary series, a single (0.5 mL) dose should be given by intramuscular injection at ages 2, 4, and 6 months; the first dose may be given as early as age 6 weeks. The recommended catch-up schedule for PRP-T vaccines (http://www.cdc.gov/vaccines/schedules/hcp/child-adolescent.html) should be followed. As previously recommended, a single booster dose should be administered to children aged 15 months through 18 months; to facilitate timely booster vaccination, Hiberix can be administered as early as age 12 months, in accordance with Hib vaccination schedules for routine and catch-up immunization (1-3).

Risk factors for adverse events after vaccinations performed during the initial hospitalization of infants born prematurely.

INTRODUCTION: There are significant delays in implementing vaccination among preterm infants. OBJECTIVES: Description of the frequency and kinds of adverse events following immunization in preterms. Establishment of the group of preterms who will distinctively be susceptible to adverse events. MATERIALS AND METHODS: Demographical, clinical data and the occurrence of adverse events after DTaP, HIB and pneumococcal vaccination among preterms during their initial hospitalization were prospectively collected with the use of an electronic data form between 1st June 2011 and 31st May 2015. The analysis was conducted on 138 patients. The groups were divided according to maturity (I: ≤ GA 28w n=73 and GA 29-36 w n=65). RESULTS: There were no statistically significant differences between the groups in the occurrence of adverse events. Out of the total group, following vaccination apnoea developed in 6 newborns (4%) and activity dysfunctions were observed in 13 newborns (10%). The occurrence of apnoea after vaccination positively correlated with the time of non-invasive ventilation and the occurrence of late infection. There were no statistically significant demographical or clinical risk factors for the development of activity dysfunctions following vaccination. CONCLUSIONS: Term vaccination in clinically stable preterm infants is a safe medical procedure. However, long-term non-invasive respiratory support and late infections are risk factors for apnea following vaccinations. In these patients vaccinations should be considered during hospitalization.

Adverse events following Haemophilus influenzae type b vaccines in the Vaccine Adverse Event Reporting System, 1990-2013.

OBJECTIVE: To characterize adverse events (AEs) after Haemophilus influenzae type b (Hib) vaccines reported to the US Vaccine Adverse Event Reporting System (VAERS), a spontaneous reporting surveillance system. STUDY DESIGN: We searched VAERS for US reports after Hib vaccines among reports received from January 1, 1990, to December 1, 2013. We reviewed a random sample of reports and accompanying medical records for reports classified as serious. All reports of death were reviewed. Physicians assigned a primary clinical category to each reviewed report. We used empirical Bayesian data mining to identify AEs that were disproportionally reported after Hib vaccines. RESULTS: VAERS received 29,747 reports after Hib vaccines; 5179 (17%) were serious, including 896 reports of deaths. Median age was 6 months (range 0-1022 months). Sudden infant death syndrome was the stated cause of death in 384 (51%) of 749 death reports with autopsy/death certificate records. The most common nondeath serious AE categories were neurologic (80; 37%), other noninfectious (46; 22%) (comprising mainly constitutional signs and symptoms); and gastrointestinal (39; 18%) conditions. No new safety concerns were identified after clinical review of reports of AEs that exceeded the data mining statistical threshold. CONCLUSION: Review of VAERS reports did not identify any new or unexpected safety concerns for Hib vaccines.

The immunogenicity, safety, and consistency of an Indonesia combined DTP-HB-Hib vaccine in expanded program on immunization schedule.

BACKGROUND: WHO recommended incorporation of Haemophilus influenzae type b (Hib) vaccination into immunization program. Indonesia would adopt Hib as a National Immunization Program in 2013. We aimed at analyzing immunogenicity, safety, and consistency of a new combined DTP-HB-Hib (diphtheria-tetanus-pertussis-Hepatitis B-Haemophilus influenza B) vaccine. METHODS: A prospective, randomized, double blind, multicenter, phase III study of Bio Farma DTP-HB-Hib vaccine conducted in Jakarta and Bandung, August 2012 - January 2013. Subjects were divided into three groups with different batch number. Healthy infants 6-11 weeks of age at enrollment were immunized with 3 doses of DTP-HB-Hib vaccine with interval of 4 weeks, after birth dose of hepatitis B vaccine. Blood samples obtained prior to vaccination and 28 days after the third dose. Safety measures recorded until 28 days after each dose. RESULTS: Of 600 subjects, 575 (96 %) completed study protocol. After 3 doses, 100.0 and 96.0 % had anti-PRP concentration ≥0.15 and ≥1.0 µg/ml. Anti-diphtheria and anti-tetanus concentration ≥0.01 IU/ml detected in 99.7 and 100.0 %; while concentration ≥0.1 IU/ml achieved in 84.0 and 97.4 %. Protective anti-HBs found in 99.3 %. The pertussis vaccine response rate was 84.9 %. None Serious Adverse events (SAEs) considered related to study vaccine or procedure. CONCLUSIONS: The 3-dose of DTP-HB-Hib was immunogenic, well tolerated and suitable for replacement of licensed-equivalent vaccines based on immunologic and safety profiles. TRIAL REGISTRATION: NCT01986335 - October 30(th) 2013.

SAFETY OF A CRM197-CONJUGATED HAEMOPHILUS INFLUENZAE TYPE B VACCINE IN KOREAN CHILDREN.

Haemophilus influenzae type b (Hib) is a major cause of meningitis and pneumonia with high morbidity and mortality rates in young children. The introduction of effective and well-tolerated conjugate Hib vaccines, has nearly eradicated this disease in many countries. We investigated the safety of the Hib PRP-CRM197 vaccine in a multi-center post-marketing surveillance (PMS) study. Korean children (N = 764) aged 1-33 months were enrolled when receiving a routine primary immunization or a booster vaccine with Hib PRP-CRM197 and solicited and unsolicited adverse events (AEs) were recorded using a diary card for 7 and 28 days after each vaccination, respectively. In this study, AEs were reported by 66% of subjects but were generally mild, with 42% of subjects reporting solicited AEs and 46% reporting unsolicited AEs. Among the unsolicited AEs, 98% were determined to be unrelated to the study vaccine. The studied Hib PRP-CRM197 vaccine was well tolerated by the study group and found to have a similar safety profile to that reported in other clinical studies. This vaccine is suitable for routine immunization against Hib disease among Korean children. AEs due to this vaccine will continue to be monitored.

IMMUNOGENICITY AND SAFETY OF QUINVAXEM® (DIPHTHERIA, TETANUS, WHOLE-CELL PERTUSSIS, HEPATITIS B AND HAEMOPHILUS INFLUENZAE TYPE B VACCINE) GIVEN TO VIETNAMESE INFANTS AT 2 TO 4 MONTHS OF AGE.

Vietnam plans to replace the routine childhood diphtheria, pertussis and tetanus combination (DPT) vaccine with a pentavalent vaccine. The present study was performed to assess the immunogenicity and safety of the combined diphtheria, tetanus, whole-cell pertussis, hepatitis B (HepB), and Haemophilus influenzae type b (Hib) (DTwP-HepB-Hib) Quinvaxem® vaccine in children. A total of 131 infants received the Quinvaxem® vaccine at 2, 3 and 4 months. Antibody levels were measured at baseline, at one month after the third injection and one year after the first injection. Seroprotection rates were high for each vaccine antigen at one month after the third dose: 93.1% for diphtheria, 98.5% for tetanus, 99.2% for pertussis (seroconversion rate), 93.1% for HepB, and 100% for Hib (anti-PRP ≥ 0.15 µg/ml). The rate of children with protective antibodies persisting at one year after the first dose was 88.4% for diphtheria, 49.6% for pertussis, 82.2% for tetanus, 76.7% for HepB and 97.7% for Hib (anti-PRP ≥ 0.15 µg/ml). The Quinvaxem® vaccine was well tolerated and has a low rate of adverse events. Quinvaxem® given at 2, 3 and 4 months of age was immunogenic and safe for primary immunization among infants in Vietnam.