Search

Heterologous Sinovac-CoronaVac booster(s) in 12-17-year-olds who had a moderate/severe reaction to Pfizer-BNT162b2 mRNA vaccine was found to safe with no serious adverse events reported. In those primed with 1 dose of Pfizer-BNT162b2 vaccine, subsequent boosters with 2 doses of Sinovac-CoronaVac vaccines achieved neutralizing antibody levels which were comparable to those who had received 2 doses of Pfizer-BNT162b2 vaccines followed by 1 dose of Sinovac-CoronaVac vaccination. Adolescents with 1 Pfizer-BNT162b2 followed by 2 Sinovac-CoronaVac vaccines developed T-cell responses against broad peptides including membrane, nucleoprotein 1 and 2 but levels were highest for Spike protein and lasted until day 150 post-vaccination., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: [Chia-Yin CHong reports financial support was provided by Government of Singapore Ministry of Health. Chee-Fu Yung reports financial support was provided by National Medical Research Council.]., (Copyright © 2024. Published by Elsevier India Pvt Ltd.)

Kawasaki disease (KD) is a systemic vasculitis mainly affecting young children and the leading cause of acquired heart disease in developed countries. We performed a self-controlled case series analysis to investigate the association between PCV13 and KD. All hospitalized KD cases <2 y old from our hospital in Singapore from 2010 to 2014 were included. Complete KD cases were classified based on the definitions of the American Heart Association. During the study period, 288 KD cases were identified. A total of 21 KD cases (12 were classified as Complete KD) had date of onset within the risk interval of day 1 to day 28 post PCV13. The age-adjusted Relative Incidence (RI) for KD following PCV13 dose 1, dose 2 and dose 3 were 1.40 (95%CI, 0.72 to 2.71), 1.23 (95% CI, 0.62 to 2.44) and 0.34 (95% CI, 0.08 to 1.40) respectively. There were seven Complete KD cases with onset during the risk interval after dose 1 of PCV13 (age-adjusted RI 2.59, 95%confidence interval (CI), 1.16 to 5.81). We did not detect a significant increased risk for overall KD among PCV13 recipients. However, a significant association between PCV13 and Complete KD was noted following receipt of the first dose of PCV13.

Background: Antibody titres and vaccine effectiveness decline within 6 months after influenza vaccination in older adults. Biannual vaccination may be necessary to provide year-round protection in the tropics, where influenza circulates throughout the year., Methods: Tropical Influenza Control Strategies (TROPICS1) was a single-center, 1:1 randomized, observer-blinded, active-comparator-controlled, superiority study in 200 community-resident adults aged ≥65 years. Participants received a standard-dose trivalent inactivated influenza vaccination (IIV3) at enrollment, and either tetanus-diphtheria-pertussis vaccination or IIV3 6 months later. The primary outcome was the proportion of participants with haemagglutination-inhibition (HI) geometric mean titre (GMT) ≥1:40 1 month after the second vaccination (month 7). Secondary outcomes included GMTs to month 12, the incidence of influenza-like illness (ILI), and adverse reactions after vaccination., Results: At month 7, the proportion of participants with an HI tire ≥1:40 against A/H1N1 increased by 21.4% (95% confidence interval [CI] 8.6-33.4) in the semiannual vaccination group. This proportion was not significantly higher for A/H3N2 (4.3, 95% CI -1.1-10.8) or B (2.1, 95% CI -2.0-7.3). Semiannual vaccination significantly increased GMTs against A/H1N1 and A/H3N2, but not B, at month 7. Participants receiving a repeat vaccination of IIV3 reported a significantly lower incidence of ILI in the 6 months after the second vaccination (relative vaccine effectiveness 57.1%, 95% CI 0.6-81.5). The frequency of adverse events was similar after the first and second influenza vaccinations., Conclusions: Semiannual influenza vaccination in older residents of tropical countries has the potential to improve serological measures of protection against infection. Alternative vaccination strategies should also be studied., Clinical Trials Registration: NCT02655874., (© The Author(s) 2018. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.)

Background: The seasonal influenza vaccine is less effective in older people and a single dose is unlikely to provide the year-round protection necessary for tropical climates which have year-round influenza virus activity. This study aims to assess the effect of a trivalent inactivated influenza vaccine (IIV3) booster at 180 days on haemagglutination-inhibition (HI) antibody titres for each of the influenza strains present in the administered vaccine in older people aged 65 years or above in Singapore., Methods/design: This is a single-centre, randomised, observer-blind, active-comparator controlled, parallel-group, phase IV trial in 200 adults aged 65 years or older. Study participants will be assigned to one of two groups in a 1:1 ratio and followed for 1 year, with five scheduled visits. The control group will receive IIV3 at day 1, and an active comparator (Tetanus-diphtheria-pertussis vaccine) at day 180. Participants in the experimental group will receive IIV3 containing the same strains at day 1 and day 180. Endpoints are immunological, and include measures of HI titres, microneutralisation titres (MN) and cell-mediated immunity from first vaccination up to day 360., Discussion: If superiority of 6-monthly influenza vaccination is demonstrated, this study could form the basis for a larger clinical trial with influenza infection as the primary endpoint., Trial Registration: ClinicalTrials.gov, ID: NCT02655874 . Registered on 12 January 2016.

Objective: To investigate the association between monovalent human rotavirus vaccine (RV1) and intussusception among Asian infants and the impact of older age of vaccination. To perform risk-benefit analysis of RV1 vaccination programs in Singapore., Study Design: We performed a self-controlled case series by extracting intussusception cases in infants aged <12 months from hospital databases (2005-2012) and with vaccination histories from a national immunization registry. Relative incidences were calculated by comparing incidence during defined risk periods after vaccination with times outside these periods. In the risk benefit analysis, we estimated excess intussusception hospitalization in relation to the number of infants vaccinated for hypothetical vaccination coverage scenarios., Results: There were 86 infants hospitalized with intussusception; 20 cases had received at least 1 dose of RV1. Nearly all (19) had received their first dose at age >12 weeks old. The age-adjusted relative incidence of intussusception in the 1- to 7-day period post dose one was 8.36 (95% CI 2.42-28.96). Of all childhood hospitalizations because of rotavirus, 71% (570 cases) could be prevented with 90% vaccination coverage. There would be approximately 1 excess intussusception case per 65,000 infants vaccinated., Conclusions: Risk of intussusception increases about 8-fold during 1-7 days after receipt of first dose RV1 in infants of Chinese, Malay, and Indian ethnicity in Singapore, Asia. High vaccine coverage program in Singapore would be beneficial with only a low risk of excess intussusception. The relative risk of intussusception post-RV1 vaccination is not higher in Asia despite differences in background intussusception incidence compared with US and Australia, or older age of vaccination., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Introduction: From 2011 to 2012, we received an unexpectedly high number of reports of suppurative lymphadenitis following administration of a BCG vaccine used in our childhood vaccination programme in Singapore. We sought to determine the local incidence rates of BCG-associated suppurative lymphadenitis across the 2009 to 2012 vaccinated cohorts, and to analyse the potential factors contributing to this outbreak., Methods: Reports of lymphadenitis following BCG vaccination from an AEFI active surveillance system at the KK Women's and Children's Hospital (KKH) and passive surveillance data from other healthcare institutions were reviewed. All valid reports received from January 2009 to December 2013 involving neonates vaccinated with the BCG vaccine in 2009 to 2012 that met case definitions were included in our analysis. Details of the demographics and vaccination history of the child, and statistics from the local vaccination programme were also obtained. Potential contributory factors were selected for further investigation based on a literature review of similar outbreaks overseas., Results: We identified 283 cases of lymphadenitis, of which 76% were suppurative. A spike in suppurative lymphadenitis cases was seen in the 2011 vaccinated cohort, with an incidence rate of 3.16 per 1000 vaccinees, as compared to 0.71 to 0.85 per 1000 in the 2009, 2010 and 2012 cohorts. Our investigations identified the likely cause of the outbreak to be batch-related, arising from manufacturing issues encountered by the manufacturer, after ruling out vaccine administration-related and host-related factors., Conclusions: The three-fold spike in BCG-associated suppurative lymphadenitis cases observed in the 2011 vaccinated cohort, possibly due to batch-to-batch variation of the vaccine, highlights that manufacturing controls can continue to be a challenge. Development of a more sensitive assay to test the reactogenicity of the BCG vaccine may help reduce the occurrence of such outbreaks and improve public confidence in the nation's vaccination programme., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Introduction: In Singapore, reporting of adverse events following immunization (AEFI) was historically passive. In 2009, Health Sciences Authority collaborated with KK Women's and Children's Hospital to perform active surveillance for AEFI. We report the methodology and initial findings of this surveillance following childhood vaccines., Methods: From April 2010 to March 2012, we screened all paediatric admissions for possible relationships to vaccination, excluding elective admissions, and performed causality assessment for each case using standardized definitions for certain, probable, possible and unlikely. Baseline demographics, data on implicated vaccines and clinical details including severity and outcomes were collected. Total hospital admissions were used to calculate rates of AEFI., Results: We screened 45,571 (80%) of 56,526 admissions, and evaluated 1988 (4.4%) children. Median age at presentation was 3.1 months, while median interval from vaccination to symptom onset was 6 days. There were 311 (15.6%) children with AEFI that were considered possibly, probably or certainly associated with vaccines. However, 98.8% recovered without any long-term sequelae. The hospital-based active surveillance of AEFI enabled the detection of a 5-fold increase (95% CI 1.2-33.1) in BCG-associated regional lymphadenitis in April 2010, which triggered follow-up safety analysis to guide public health advice., Conclusions: Hospital-based active surveillance can enhance signal detection and follow-up investigations of AEFI. Subsequently, public health bodies are better equipped to maintain public confidence in vaccination programmes and physicians are able to provide relevant advice to parents. It also allows for a better understanding of risk-benefit ratios of specific vaccines and aids the generation of public health vaccination policy., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

We analyzed data from hospital admissions and enhanced mumps surveillance to assess mumps complications during the largest mumps outbreak in England and Wales, 2004-2005, and their association with mumps vaccination. When compared with nonoutbreak periods, the outbreak was associated with a clear increase in hospitalized patients with orchitis, meningitis, and pancreatitis. Routine mumps surveillance and hospital data showed that 6.1% of estimated mumps patients were hospitalized, 4.4% had orchitis, 0.35% meningitis, and 0.33% pancreatitis. Enhanced surveillance data showed 2.9% of mumps patients were hospitalized, 6.1% had orchitis, 0.3% had meningitis, and 0.25% had pancreatitis. Risk was reduced for hospitalization (odds ratio [OR] 0.54, 95% confidence interval [CI] 0.43-0.68), mumps orchitis (OR 0.72, 95% CI 0.56-0.93) and mumps meningitis (OR 0.28, 95% CI 0.14-0.56) when patient had received 1 dose of measles, mumps, and rubella vaccine. The protective effect of vaccination on disease severity is critical in assessing the total effects of current and future mumps control strategies.