METHODS: A qualitative study design involving individual both face-to-face and online in-depth interview was used. The topic guide was developed from the Health Belief Model theoretical framework. Seven face-to-face and seven online interviews were conducted with parents in the Klang Valley (an urban area) who had refused childhood vaccination. All interviews were audio-recorded, transcribed verbatim and checked. Thematic approach was used to analyze the data. Data was collected until data saturation was reached.

RESULTS: Findings were summarized into two main categories: Personal Health Beliefs and Vaccine Related Concerns. Six personal health beliefs were identified: lack of confidence in modern medicine and health care personnel, pharmaceutical conspiracy to sell medicines, preference to a natural approach to health, personal instincts, religious beliefs and having a partner with similar beliefs. Four main vaccine-related concerns were identified: negative effects and content concerns, doubts of necessity and lack of information and knowledge regarding vaccines. Parents recommended that more empathy from healthcare professionals and evidence on safety and content purity would help them reconsider vaccination.

MATERIALS AND METHODS: Plasma samples were collected prevaccination, 2 weeks and 6 months post-vaccination and tested for total immunoglobulin levels using ELISA method.

RESULTS: A small percentage of HCW (2.2%, 15/677) had elevated anti-S antibody levels in their pre-vaccination plasma samples (median 20.4, IQR 5.8), indicating that they were exposed to SARS-CoV-2 infection prior to vaccination. The mRNA vaccine significantly increased anti-S levels of both previously infected and uninfected individuals to saturation levels (median 21.88, IQR.0.88) at 2 weeks postsecond dose of the vaccine. At 6 months post-vaccination, the antibody levels appeared to be maintained among the recipients of the mRNA vaccine. However, at this time point, anti-S antibody levels were lower in individuals given inactivated vaccine (median 20.39, IQR 7.31, n=28), and interestingly, their antibody levels were similar to anti-S levels in pre-vaccination exposed individuals. Antibody levels were not different between the sexes.

METHODS: We enrolled participants who were vaccinated through the SISONKE South African clinical trial of the Ad26.CoV2.S vaccine in healthcare workers (HCWs). PLWH in this group had well-controlled HIV infection. We also enrolled unvaccinated participants previously infected with SARS-CoV-2. Neutralization capacity was assessed by a live virus neutralization assay of the Delta variant.

RESULTS: Most Ad26.CoV2.S vaccinated HCWs were previously infected with SARS-CoV-2. In this group, Delta variant neutralization was 9-fold higher compared with the infected-only group and 26-fold higher relative to the vaccinated-only group. No decrease in Delta variant neutralization was observed in PLWH relative to HIV-negative participants. In contrast, SARS-CoV-2-infected, unvaccinated PLWH showed 7-fold lower neutralization and a higher frequency of nonresponders, with the highest frequency of nonresponders in people with HIV viremia. Vaccinated-only participants showed low neutralization capacity.

MATERIALS AND METHODS: A cross-sectional study was conducted among parents of children below 5 years of age, from July to September 2022 at two urban primary care clinics in the Cheras district of Kuala Lumpur. Hesitance and perception of the COVID-19 vaccine were assessed using a self-administered questionnaire.

RESULTS: A total of 219 completed entries were analysed. The rate of COVID-19 vaccine hesitance for children below the age of 5 was 64.4% (n=141). Univariate analysis showed that vaccine hesitancy was associated with parental age and Muslim religion. The multivariate model showed that younger parents were more likely to be vaccine hesitant compared to older parents. A 1-year increase in parental age showed a 13% decrease in the odds of vaccine hesitancy (AOR 0.87, 95% CI 0.80-0.96). Muslim parents were also more likely to be vaccine hesitant compared to non-Muslim parents (AOR 2.46, 95% CI 1.26-4.79). Most parents perceived correctly that the vaccine can prevent complications and the spread of the disease. However, their main barriers to vaccination were concerns regarding side effects, safety and effectiveness of the vaccine.

RESEARCH DESIGN AND METHODS: A combined cohort Markov decision tree model was used to compare booster vaccination with an Omicron-adapted bivalent COVID-19 vaccine versus no booster vaccination in Malaysia. The model utilized age-specific data from January 2021 to March 2022 derived from published sources. The outcomes of interest included case numbers, hospitalizations, deaths, medical costs, and productivity losses. The population was stratified into high-risk and standard-risk subpopulations, and the study evaluated the benefits of increased coverage in different age and risk groups.

RESULTS: Vaccinating only high-risk individuals and those aged ≥ 65 years was estimated to avert 274,313 cases, 33229 hospitalizations, 2,434 deaths, Malaysian ringgit (MYR) 576 million in direct medical costs, and MYR 579 million in indirect costs. Expanding vaccination coverage in the standard-risk population to 75% was estimated to avert more deaths (31%), hospitalizations (155%), infections (206%), direct costs (206%), and indirect costs (281%).

MATERIALS AND METHODS: A cross-sectional study was conducted using an online survey between February and May 2022, with 423 respondents. The questionnaire consisted of socio-demographic, assessment of knowledge level and acceptance level towards COVID-19 vaccine. The descriptive analysis and non-parametric tests were employed to investigate the study outline objectives.

RESULTS: Of all 423 participants, 293 (69.3%) of the participants had a high level of knowledge about the COVID- 19 vaccine (median knowledge score 6; IQR = 3), and 239 (56.5%) were reported to have a low level of vaccine acceptance (median acceptance scores 4; IQR=2). The knowledge level towards the COVID-19 vaccine was significantly associated with the vaccine acceptance level (p<0.001).

METHODS: The demographic and clinical characteristics of COVID-19 cases and the district's vaccination coverage were described. Vaccination coverage was plotted against COVID-19 cases on the epidemic curve. The χ2 test was used to examine the differences between the vaccination status of COVID-19 cases and severity category, hospitalization status and mortality.