Seroprevalence and Shifting Endemicities of Hepatitis A Virus Infection in Two Different Geographical Areas in the Philippines.

INTRODUCTION: Infection with hepatitis A virus (HAV) is often asymptomatic in young children, but most adolescents and adults will have symptoms ranging from nausea and tiredness to acute liver failure and even death. The risk of severe disease is higher in older adults and people with pre-existing liver disease. Immunization is recommended in regions with low HAV endemicity levels, i.e., where people get infected later in life. In the Philippines, recent epidemiologic data on HAV infection are lacking. The objective of this study was to assess age-specific seroprevalence and evaluate risk factors associated with HAV seropositivity. METHODS: People from two geographic areas (urban and rural) were recruited/enrolled and stratified by age group. HAV-specific immunoglobulin G (IgG) antibodies were measured with a chemiluminescent microparticle immunoassay. Sociodemographic parameters, hepatitis medical history, disease knowledge, hygiene measures and sanitation were assessed via a purpose-made questionnaire. Age at midpoint of population immunity (AMPI) was estimated using Kaplan-Meier curves. Logistic regression analyses were carried out to determine factors that were statistically significantly associated (p < 0.05) with HAV seropositivity. RESULTS: Overall, 1242 participants were included in the analysis; 250/602 (41.5%) participants from urban regions and 283/640 (44.2%) participants from rural regions tested positive for HAV IgG antibodies. AMPI was 35 and 37 years for the rural and urban region, respectively. Higher education was associated with lower HAV seropositivity prevalence ratios, while not living in the same region for the last 5 years, regularly consuming street food and lack of handwashing after defecation were associated with a higher likelihood of HAV seropositivity. CONCLUSION: Results suggest that HAV endemicity is low in the Philippines. Factors associated with HAV seropositivity were traveling, consuming street food and lack of basic hygienic gestures. Immunization might be an option to protect vulnerable populations against severe hepatitis A disease.

Hepatitis A virus (HAV) is transmitted via the fecal-oral route through consumption of contaminated food or water or by close contact with an infected person. In children, HAV is usually of no concern, but in adults and people with existing liver disease, HAV infection can lead to severe symptoms and even death. In areas where most people get hepatitis during childhood (high endemicity), vaccination is not required, since people acquire life-long immunity after infection. In regions with low and intermediate HAV endemicity, people may remain at risk of infection later in life and vaccination could be considered to prevent severe HAV disease and its associated complications. In the Philippines, the current endemicity level is unknown. The goal of this study was to determine the endemicity level in the Philippines and to determine risk factors for HAV infection. We measured the proportion of people (by age group) who had previously been infected with HAV. Results showed that by age of 5 years < 20% of the study population was infected by HAV. By the age of 37 years in the urban population and 35 years in the rural population, 50% of people tested positive for HAV antibodies, indicating previous infection. This means that the Philippines has low HAV endemicity. Risk factors for HAV seropositivity were traveling, regularly eating street food and not washing hands after defecation. Vaccination against HAV might be of benefit in the Philippines, especially early in life to prevent most severe outcomes in adulthood.

Safety and immunogenicity of SCB-2019, an adjuvanted, recombinant SARS-CoV-2 trimeric S-protein subunit COVID-19 vaccine in healthy 12-17 year-old adolescents.

We previously demonstrated the efficacy of the COVID-19 vaccine candidate, SCB-2019, in adults in the SPECTRA phase 2/3 efficacy study. We extended the study to include 1278 healthy 12-17-year-old adolescents in Belgium, Colombia, and the Philippines who received either two doses of SCB-2019 or placebo 21 days apart, to assess immunogenicity as neutralizing antibodies against prototype SARS-CoV-2 and variants of concern, and safety and reactogenicity as solicited and unsolicited adverse events with a comparator group of young adults (18-25 years). In participants with no evidence of prior SARS-CoV-2 infection SCB-2019 immunogenicity in adolescents was non-inferior to that in young adults; respective geometric mean neutralizing titers (GMT) against prototype SARS-CoV-2 14 days after the second vaccination were 271 IU/mL (95% CI: 211-348) and 144 IU/mL (116-178). Most adolescents (1077, 84.3%) had serologic evidence of prior SAR-CoV-2 exposure at baseline; in these seropositive adolescents neutralizing GMTs increased from 173 IU/mL (135-122) to 982 IU/mL (881-1094) after the second dose. Neutralizing titers against Delta and Omicron BA SARS-CoV-2 variants were also increased, most notably in those with prior exposure. SCB-2019 vaccine was well tolerated with generally mild or moderate, transient solicited and unsolicited adverse events that were comparable in adolescent vaccine and placebo groups except for injection site pain - reported after 20% of SCB-2019 and 7.3% of placebo injections. SCB-2019 vaccine was highly immunogenic against SARS-CoV-2 prototype and variants in adolescents, especially in those with evidence of prior exposure, with comparable immunogenicity to young adults. Clinical trial registration: EudraCT 2020-004272-17; ClinicalTrials.gov NCT04672395.

Immunogenicity of an adjuvanted SARS-CoV-2 trimeric S-protein subunit vaccine (SCB-2019) in SARS-CoV-2-naïve and exposed individuals in a phase 2/3, double-blind, randomized study.

BACKGROUND: We evaluated immunogenicity of SCB-2019, a subunit vaccine candidate containing a pre-fusion trimeric form of the SARS-CoV-2 spike (S)-protein adjuvanted with CpG-1018/alum. METHODS: The phase 2/3, double-blind, randomized SPECTRA trial was conducted in five countries in participants aged ≥ 18 years, either SARS-CoV-2-naïve or previously exposed. Participants were randomly assigned to receive two doses of SCB-2019 or placebo administered intramuscularly 21 days apart. In the phase 2 part of the study, on days 1, 22, and 36, neutralizing antibodies were measured by pseudovirus and wild-type virus neutralization assays to SARS-CoV-2 prototype and variants, and ACE2-receptor-binding antibodies and SCB-2019-binding antibodies were measured by ELISA. Cell-mediated immunity was measured by intracellular cytokine staining via flow cytometry. RESULTS: 1601 individuals were enrolled between 24 March and 13 September 2021 and received at least one vaccine dose. Immunogenicity analysis was conducted in a phase 2 subset of 691 participants, including 428 SARS-CoV-2-naïve (381 vaccine and 47 placebo recipients) and 263 SARS-CoV-2-exposed (235 vaccine and 28 placebo recipients). In SARS-CoV-2-naïve participants, GMTs of neutralizing antibodies against prototype virus increased 2 weeks post-second dose (day 36) compared to baseline (224 vs 12.7 IU/mL). Seroconversion rate was 82.5 %. In SARS-CoV-2-exposed participants, one SCB-2019 dose increased GMT of neutralizing antibodies by 48.3-fold (1276.1 IU/mL on day 22) compared to baseline. Seroconversion rate was 92.4 %. Increase was marginal post-second dose. SCB-2019 also showed cross-neutralization capability against nine variants, including Omicron, in SARS-CoV-2-exposed participants at day 36. SCB-2019 stimulated Th1-biased cell-mediated immunity to the S-protein in both naïve and exposed participants. The vaccine was well tolerated, no safety concerns were raised from the study. CONCLUSIONS: A single dose of SCB-2019 was immunogenic in SARS-CoV-2-exposed individuals, whereas two doses were required to induce immune response in SARS-CoV-2-naïve individuals. SCB-2019 elicited a cross-neutralizing response against emergent SARS-CoV-2 variants at antibody levels associated with clinical protection, underlining its potential as a booster. CLINICALTRIALS: gov: NCT04672395; EudraCT: 2020-004272-17.

Invasive meningococcal disease in Malaysia, Philippines, Thailand, and Vietnam: An Asia-Pacific expert group perspective on current epidemiology and vaccination policies.

Invasive meningococcal disease (IMD) imposes a significant burden on the global community due to its high case fatality rate (4-20%) and the risk of long-term sequelae for one in five survivors. An expert group meeting was held to discuss the epidemiology of IMD and immunization policies in Malaysia, Philippines, Thailand, and Vietnam. Most of these countries do not include meningococcal immunization in their routine vaccination programs, except for high-risk groups such as immunocompromised people and pilgrims. It is difficult to estimate the epidemiology of IMD in the highly diverse Asia-Pacific region, but available evidence indicate serogroup B is increasingly dominant. Disease surveillance systems differ by country. IMD is not a notifiable disease in some of them. Without an adequate surveillance system in the region, the risk and the burden of IMD might well be underestimated. With the availability of new combined meningococcal vaccines and the World Health Organization roadmap to defeat bacterial meningitis by 2030, a better understanding of the epidemiology of IMD in the Asia-Pacific region is needed.

A Phase 3, Multicenter, Randomized, Controlled Trial to Evaluate Immune Equivalence and Safety of Multidose and Single-dose Formulations of Vi-DT Typhoid Conjugate Vaccine in Healthy Filipino Individuals 6 Months to 45 Years of Age.

Trial Design: Phase 3, randomized, controlled, multicenter, equivalence trial. Methods: Recruitment of participants occurred between 04Februray2020 and 15July2020 at four centers in the Philippines: University of the East - Ramon Magsaysay Memorial Medical Center Inc., Quezon City; University of Philippines Manila - National Institute of Health, Ermita Manila; Asian Hospital and Medical Center, Metro Manila, Philippines Study; and Medical Research Unit, Tropical Disease Foundation, Makati City, Metro Manila, Philippines. Participants: 1800 adults and children 6-months to 45-years of age. Interventions: Participants received a single injection of multidose (MD) or single dose (SD) Vi-DT as test vaccines or meningococcal conjugate vaccine as a comparator. Objective: To evaluate immune equivalence of SD and MD formulations of Vi-DT, and to assess the safety of both formulations compared with comparator vaccine. Outcome Measurement: Blood draw for immunogenicity was performed at baseline prior to vaccine receipt and at four weeks after vaccination for a subset of participants to determine anti-Vi IgG geometric mean titers (GMT) and seroconversion rates. The primary outcome was comparison of anti Vi-IgG seroconversion and GMT between the two formulations of Vi-DT at 4 weeks following vaccine administration. Immune equivalence of MD and SD formulations was confirmed when the two-tailed 95% confidence interval (CI) of the GMT ratio is within [0.67, 1.5] at a two-sided significance level of 0.05. All participants were followed for safety events for six months after vaccine administration. Randomization: Participants were randomized to receive SD Vi-DT, MD Vi-DT, or meningococcal conjugate vaccines in 2.5:2.5:1 allocation ratio. Blinding: Study participants and observers were blinded to treatment assignment. Findings: Immune equivalence of SD (n=252) and MD (n=247) formulations was confirmed by anti-Vi IgG GMT ratio of 1.14 (95%CI: 0.91, 1.43) with respective GMTs in the MD and SD groups of 640.62 IU/mL (95%CI: 546.39, 751.11) and 562.57 IU/mL (95%CI: 478.80, 661.00) (p=0.259). Similarly, anti-Vi IgG seroconversion rate difference between the two formulations of ‒0.43% (95%CI: -4.42, 3.56) confirmed immune equivalence with corresponding seroconversion rates of 98.38% (95%CI: 95.91, 99.37) and 98.81% (95%CI: 96.56, 99.59) in MD and SD Vi-DT formulations, respectively (p=0.722). Both formulations of Vi-DT had a satisfactory safety profile - all five serious adverse events reported during the study were unrelated to the investigational product. Interpretation: The MD and SD formulations of Vi-DT elicited robust and equivalent immune responses following one dose vaccination, and both formulations demonstrated a favorable safety profile. Trial Registration: ClinicalTrials.gov: NCT04204096. Funding: This study was funded by the Bill & Melinda Gates Foundation (OPP 1115556).

Efficacy of the adjuvanted subunit protein COVID-19 vaccine, SCB-2019: a phase 2 and 3 multicentre, double-blind, randomised, placebo-controlled trial.

BACKGROUND: A range of safe and effective vaccines against SARS CoV 2 are needed to address the COVID 19 pandemic. We aimed to assess the safety and efficacy of the COVID-19 vaccine SCB-2019. METHODS: This ongoing phase 2 and 3 double-blind, placebo-controlled trial was done in adults aged 18 years and older who were in good health or with a stable chronic health condition, at 31 sites in five countries (Belgium, Brazil, Colombia, Philippines, and South Africa). The participants were randomly assigned 1:1 using a centralised internet randomisation system to receive two 0·5 mL intramuscular doses of SCB-2019 (30 µg, adjuvanted with 1·50 mg CpG-1018 and 0·75 mg alum) or placebo (0·9% sodium chloride for injection supplied in 10 mL ampoules) 21 days apart. All study staff and participants were masked, but vaccine administrators were not. Primary endpoints were vaccine efficacy, measured by RT-PCR-confirmed COVID-19 of any severity with onset from 14 days after the second dose in baseline SARS-CoV-2 seronegative participants (the per-protocol population), and the safety and solicited local and systemic adverse events in the phase 2 subset. This study is registered on EudraCT (2020-004272-17) and ClinicalTrials.gov (NCT04672395). FINDINGS: 30 174 participants were enrolled from March 24, 2021, until the cutoff date of Aug 10, 2021, of whom 30 128 received their first assigned vaccine (n=15 064) or a placebo injection (n=15 064). The per-protocol population consisted of 12 355 baseline SARS-CoV-2-naive participants (6251 vaccinees and 6104 placebo recipients). Most exclusions (13 389 [44·4%]) were because of seropositivity at baseline. There were 207 confirmed per-protocol cases of COVID-19 at 14 days after the second dose, 52 vaccinees versus 155 placebo recipients, and an overall vaccine efficacy against any severity COVID-19 of 67·2% (95·72% CI 54·3-76·8), 83·7% (97·86% CI 55·9-95·4) against moderate-to-severe COVID-19, and 100% (97·86% CI 25·3-100·0) against severe COVID-19. All COVID-19 cases were due to virus variants; vaccine efficacy against any severity COVID-19 due to the three predominant variants was 78·7% (95% CI 57·3-90·4) for delta, 91·8% (44·9-99·8) for gamma, and 58·6% (13·3-81·5) for mu. No safety issues emerged in the follow-up period for the efficacy analysis (median of 82 days [IQR 63-103]). The vaccine elicited higher rates of mainly mild-to-moderate injection site pain than the placebo after the first (35·7% [287 of 803] vs 10·3% [81 of 786]) and second (26·9% [189 of 702] vs 7·4% [52 of 699]) doses, but the rates of other solicited local and systemic adverse events were similar between the groups. INTERPRETATION: Two doses of SCB-2019 vaccine plus CpG and alum provides notable protection against the entire severity spectrum of COVID-19 caused by circulating SAR-CoV-2 viruses, including the predominating delta variant. FUNDING: Clover Biopharmaceuticals and the Coalition for Epidemic Preparedness Innovations.

Safety and Immunogenicity of a New Inactivated Polio Vaccine Made From Sabin Strains: A Randomized, Double-Blind, Active-Controlled, Phase 2/3 Seamless Study.

BACKGROUND: A new inactivated polio vaccine made from Sabin strains (sIPV) was developed as part of the global polio eradication initiative. METHODS: This randomized, double-blind, active-controlled, phase 2/3 seamless study was conducted in 2 stages. Healthy infants aged 6 weeks were randomly assigned to receive 3 doses of 1 of 4 study vaccines at 6, 10, and 14 weeks of age (336 received low-, middle-, or high-dose sIPV, or conventional IPV [cIPV] in stage I, and 1086 received lot A, B, or C of the selected sIPV dose, or cIPV in stage II). The primary outcome was the seroconversion rate 4 weeks after the third vaccination. RESULTS: In stage I, low-dose sIPV was selected as the optimal dose. In stage II, consistency among the 3 manufacturing lots of sIPV was demonstrated. The seroconversion rates for Sabin and wild strains of the 3 serotypes after the 3-dose primary series were 95.8% to 99.2% in the lot-combined sIPV group and 94.8% to 100% in the cIPV group, proving the noninferiority of sIPV compared to cIPV. No notable safety risks associated with sIPV were observed. CONCLUSIONS: Low-dose sIPV administered as a 3-dose vaccination was safe and immunogenic compared to cIPV. CLINICAL TRIALS REGISTRATION: NCT03169725.

Meningococcal disease surveillance in the Asia-Pacific region (2020): The global meningococcal initiative.

The degree of surveillance data and control strategies for invasive meningococcal disease (IMD) varies across the Asia-Pacific region. IMD cases are often reported throughout the region, but the disease is not notifiable in some countries, including Myanmar, Bangladesh and Malaysia. Although there remains a paucity of data from many countries, specific nations have introduced additional surveillance measures. The incidence of IMD is low and similar across the represented countries (<0.2 cases per 100,000 persons per year), with the predominant serogroups of Neisseria meningitidis being B, W and Y, although serogroups A and X are present in some areas. Resistance to ciprofloxacin is also of concern, with the close monitoring of antibiotic-resistant clonal complexes (e.g., cc4821) being a priority. Meningococcal vaccination is only included in a few National Immunization Programs, but is recommended for high-risk groups, including travellers (such as pilgrims) and people with complement deficiencies or human immunodeficiency virus (HIV). Both polysaccharide and conjugate vaccines form part of recommendations. However, cost and misconceptions remain limiting factors in vaccine uptake, despite conjugate vaccines preventing the acquisition of carriage.

Immunogenicity and safety of an adjuvanted inactivated polio vaccine, IPV-Al, compared to standard IPV: A phase 3 observer-blinded, randomised, controlled trial in infants vaccinated at 6, 10, 14 weeks and 9 months of age.

BACKGROUND: A dose-sparing inactivated polio vaccine (IPV-Al), obtained by adsorption of inactivated virus to an aluminium hydroxide adjuvant, can help mitigate global supply and the cost constraints of IPV. The objective of this trial was to demonstrate the non-inferiority of IPV-Al to standard IPV. METHODS: This phase 3, observer-blinded, randomised, controlled trial was conducted at 5 investigational sites in the Philippines. Infants not previously vaccinated with any polio vaccines were randomised to receive three IPV-Al (n = 502) or IPV vaccinations (n = 500) at 6, 10 and 14 weeks of age plus a booster vaccination at 9 months. The primary endpoint was type-specific seroconversion, defined as an antibody titre ≥4-fold higher than the estimated maternal antibody titre and a titre ≥8, one month after the primary vaccination series. RESULTS: Seroconversion rates following primary vaccination with IPV-Al (483 infants in the per-protocol analysis set) or IPV (478 infants) were: polio type 1, 97.1% versus 99.0%; type 2, 94.2% versus 99.0%; and type 3, 98.3% versus 99.6%. IPV-Al was non-inferior to IPV, as the lower 95% confidence limits of the treatment differences were above the predefined -10%-point limit: type 1, -1.85% (-3.85; -0.05); type 2, -4.75% (-7.28; -2.52); type 3, -1.24 (-2.84; 0.13). The booster effect (geometric mean titre (GMT) post-booster / GMT pre-booster) was: type 1, 63 versus 43; type 2, 54 versus 47; type 3, 112 versus 80. IPV-Al was well tolerated with a safety profile comparable to that of IPV. Serious adverse events were recorded for 29 infants (5.8%, 37 events) in the IPV-Al group compared to 28 (5.6%, 48 events) in the IPV group. CONCLUSION: Non-inferiority of IPV-Al to IPV with respect to seroconversion was confirmed and a robust booster response was demonstrated. Both vaccines had a similar safety profile. ClinicalTrials.gov identifier: NCT03032419.

The Global Meningococcal Initiative meeting on prevention of meningococcal disease worldwide: Epidemiology, surveillance, hypervirulent strains, antibiotic resistance and high-risk populations.

INTRODUCTION: The 2018 Global Meningococcal Initiative (GMI) meeting focused on evolving invasive meningococcal disease (IMD) epidemiology, surveillance, and protection strategies worldwide, with emphasis on emerging antibiotic resistance and protection of high-risk populations. The GMI is comprised of a multidisciplinary group of scientists and clinicians representing institutions from several continents. AREAS COVERED: Given that the incidence and prevalence of IMD continually varies both geographically and temporally, and surveillance systems differ worldwide, the true burden of IMD remains unknown. Genomic alterations may increase the epidemic potential of meningococcal strains. Vaccination and (to a lesser extent) antimicrobial prophylaxis are the mainstays of IMD prevention. Experiences from across the globe advocate the use of conjugate vaccines, with promising evidence growing for protein vaccines. Multivalent vaccines can broaden protection against IMD. Application of protection strategies to high-risk groups, including individuals with asplenia, complement deficiencies and human immunodeficiency virus, laboratory workers, persons receiving eculizumab, and men who have sex with men, as well as attendees at mass gatherings, may prevent outbreaks. There was, however, evidence that reduced susceptibility to antibiotics was increasing worldwide. EXPERT COMMENTARY: The current GMI global recommendations were reinforced, with several other global initiatives underway to support IMD protection and prevention.

The Global Meningococcal Initiative: global epidemiology, the impact of vaccines on meningococcal disease and the importance of herd protection.

INTRODUCTION: The 2015 Global Meningococcal Initiative (GMI) meeting discussed the global importance of meningococcal disease (MD) and its continually changing epidemiology. Areas covered: Although recent vaccination programs have been successful in reducing incidence in many countries (e.g. Neisseria meningitidis serogroup [Men]C in Brazil, MenA in the African meningitis belt), new clones have emerged, causing outbreaks (e.g. MenW in South America, MenC in Nigeria and Niger). The importance of herd protection was highlighted, emphasizing the need for high vaccination uptake among those with the highest carriage rates, as was the need for boosters to maintain individual and herd protection following decline of immune response after primary immunization. Expert commentary: The GMI Global Recommendations for Meningococcal Disease were updated to include a recommendation to enable access to whole-genome sequencing as for surveillance, guidance on strain typing to guide use of subcapsular vaccines, and recognition of the importance of advocacy and awareness campaigns.

Safety, immunogenicity, and lot-to-lot consistency of a quadrivalent inactivated influenza vaccine in children, adolescents, and adults: A randomized, controlled, phase III trial.

BACKGROUND: Inactivated quadrivalent influenza vaccine (IIV4) containing two influenza A strains and one strain from each B lineage (Yamagata and Victoria) may offer broader protection against seasonal influenza than inactivated trivalent influenza vaccine (IIV3), containing a single B strain. This study examined the safety, immunogenicity, and lot consistency of an IIV4 candidate. METHODS: This phase III, randomized, controlled, multicenter trial in children/adolescents (9 through 17 years) and adults (18 through 60 years) was conducted in Australia and in the Philippines in 2012. The study was double-blind for IIV4 lots and open-label for IIV4 vs IIV3. Children/adolescents were randomized 2:2:2:1 and adults 10:10:10:1 to receive one of three lots of IIV4 or licensed IIV3. Safety data were collected for up to 6 months post-vaccination. Hemagglutination inhibition and seroneutralization antibody titers were assessed pre-vaccination and 21 days post-vaccination. RESULTS: 1648 adults and 329 children/adolescents received IIV4, and 56 adults and 55 children/adolescents received IIV3. Solicited reactions, unsolicited adverse events, and serious adverse events were similar for IIV3 and IIV4 recipients in both age groups. Injection-site pain, headache, malaise, and myalgia were the most frequently reported solicited reactions, most of which were mild and resolved within 3 days. No vaccine-related serious adverse events or deaths were reported. Post-vaccination antibody responses, seroconversion rates, and seroprotection rates for the 3 strains common to both vaccines were comparable for IIV3 and IIV4 in both age groups. Antibody responses to IIV4 were equivalent among vaccine lots and comparable between age groups for each of the 4 strains. IIV4 met all European Medicines Agency immunogenicity criteria for adults for all 4 strains. CONCLUSIONS: In both age groups, IIV4 was well tolerated and caused no safety concerns, induced robust antibody responses to all 4 influenza strains, and met all EMA immunogenicity criteria for adults. CLINICAL TRIAL REGISTRY NUMBER: NCT01481454.

Cost-Effectiveness Analysis of Pneumococcal Vaccination with the Pneumococcal Polysaccharide NTHi Protein D Conjugate Vaccine in the Philippines.

OBJECTIVES: To compare the cost-effectiveness of a universal mass vaccination (UMV) program with a 2 + 1 schedule of a 10-valent pneumococcal polysaccharide nontypeable Haemophilus influenzae protein D conjugate vaccine (PHiD-CV) against two strategies: 1) a no-vaccination strategy and 2) a pneumococcal 13-valent conjugate vaccine (PCV13) 2 + 1 strategy in the Philippines. METHODS: A published Markov cohort model was adapted to simulate the epidemiological and economic burden of pneumococcal diseases (meningitis, bacteremia, pneumonia, and acute otitis media) within a projected birth cohort in 2012 of 1,812,137 newborns over lifetime. Analyses were conducted at an annual discount rate of 5% from the perspective of the Philippine government. The current evaluation was updated with the best available local/regional clinical epidemiological data and published efficacy evidence. RESULTS: Compared with the no-vaccination strategy, the PHiD-CV 2 + 1 UMV program was projected to prevent 3,343 deaths due to invasive pneumococcal diseases and pneumonia and 326,862 cases of pneumococcal diseases, resulting in an incremental cost-effectiveness ratio of 50,913 pesos/quality-adjusted life-year gained, which was considered to be highly cost-effective according to the threshold recommended by the World Health Organization. In comparison with the PCV13 2 + 1 strategy, the PHiD-CV 2 + 1 strategy was estimated to have a substantial reduction in acute otitis media (127,680 cases) and therefore a cost saving of potential 92.5 million pesos assuming price parity between PHiD-CV and PCV13 (US $1 = 42.13 pesos in 2012). CONCLUSIONS: The PHiD-CV 2 + 1 UMV program is projected to be cost-effective, compared with no vaccination, and would provide substantial savings with higher quality-adjusted life-year gains as compared with the PCV13 2 + 1 strategy in the context of the Philippines.

Randomized controlled study of fractional doses of inactivated poliovirus vaccine administered intradermally with a needle in the Philippines.

OBJECTIVE: Comparison of a fractional inactivated poliovirus vaccine (IPV) dose administered intradermally (ID) to a full dose administered intramuscularly (IM). METHODS: Healthy Filipino infants were randomized to receive IPV as either a fractional (1/5(th)) dose ID by needle injection or a full dose IM at 6, 10, and 14 weeks and a booster at 15-18 months of age. Pre- and post-vaccination anti-polio 1, 2, and 3 titers were estimated. Adverse events were monitored throughout the study. RESULTS: Following primary series vaccination, anti-polio 1, 2, and 3 titers were ≥8 (1/dil) in 99-100% of participants, and the ID route was non-inferior to the IM route. Depending on the study group, antibody persistence was detected in 83-100% of participants, and the booster dose resulted in a strong anamnestic response in all groups. The incidence of adverse events in each group was similar, except for injection-site erythema (higher in the ID group). CONCLUSIONS: Primary series and booster vaccination of a fractional IPV dose administered by the ID route was highly immunogenic and well tolerated. These data confirm the medical validity of using fractional ID doses of IPV. The programmatic feasibility of implementing affordable mass vaccination programs based on this delivery mode has yet to be established.

MMR trivalent vaccine based on safety, reactogenicity and immunogenicity observed in 12-24 month-old healthy Filipino children: Evaluation of lot-to-lot consistency of a live-attenuated measles-mumps-rubella

In this double-blind, randomized single-dose study, 194 healthy Filipino children aged 12-24 months were randomized into three groups (1:1:1) to receive one of the three lots of live-attenuated measles-mumps-rubella (MMR) vaccine to assess lot-to-lot consistency in safety and immunogenicity. Adverse events were recorded during 43-day post-vaccination follow-up period. Antibody levels were measured using ELISA pre-vaccination and on Day-60. No statistically significant differences were observed across groups for overall incidences of local and general symptoms (p>0.05) or immune response rates against the three antigens (p=0.835, 0.458 and 0.222 for anti-measles, anti-mumps and anti-rubella, respectively). The three lots demonstrated consistency in their reactogenicity and immunogenicity profile.

Immunogenicity and safety of a DTaP-IPV//PRP approximately T combination vaccine given with hepatitis B vaccine: a randomized open-label trial.

OBJECTIVE: To determine seroprotection and vaccine response rates produced by a diphtheria-tetanus-acellular pertussis-inactivated poliovirus-Haemophilus influenzae type-b conjugate (DTaP-IPV//PRP approximately T) vaccine containing a polyribosyl-ribitol-phosphate (PRP)-tetanus toxoid conjugate (Pentaxim) and given with a hepatitis B vaccine. METHODS: In this multicentre open-label trial, 424 infants who received DTaP-IPV//PRP approximately T at 6, 10 and 14 weeks of age were also randomized to receive hepatitis B vaccine at either 6, 10 and 14 weeks or 0, 6 and 14 weeks of age. Antibody levels were determined at 6 and 18 weeks of age, and reactogenicity was monitored using parental reports. FINDINGS: Immunogenicity was high for all vaccine antigens and was similar to that in a historical control study. After primary vaccination, 98.7% of all infants had an anti-PRP antibody titre > 0.15 microg/ml. Seroprotection against poliovirus type-1, -2 and -3 and tetanus was obtained in all infants, and against diphtheria, in 97.1%. Pertussis seroconversion, defined as a > fourfold increase in antibody titre, occurred in 95.3% for anti-pertussis toxoid antibody and in 89.0% for anti-filamentous haemagglutinin antibody. The hepatitis B seroprotection rate was 99.5% with administration at 0, 6 and 14 weeks, and 97.8%, at 6, 10 and 14 weeks. However, the antibody titre was higher with the 0, 6 and 14-week schedule (601 mIU/ml versus 207 mIU/ml). The reactogenicity of both vaccines was low. CONCLUSION: The DTaP-IPV//PRP approximately T vaccine was highly immunogenic. The anti-hepatitis B antibody response was seroprotective with both schedules, though the antibody titre was higher with the 0, 6 and 14-week schedule.