Cost-Effectiveness Analysis for Influenza Vaccination Coverage and Timing in Tropical and Subtropical Climate Settings: A Modeling Study.

BACKGROUND: The lack of seasonality in influenza epidemics in the tropics makes the application of well-established temperate zone national vaccination plans challenging. OBJECTIVES: We developed an individual-based simulation model to study optimal vaccination scheduling and assess cost-effectiveness of these vaccination schedules in scenarios of no influenza seasonality and the seasonality regimes of Singapore, Taipei, and Tokyo. METHODS: The simulation models heterogeneities in human contact networks, levels of protective antibodies following infection, the effectiveness of the influenza vaccine, and seasonality. Using a no intervention baseline, we consider 3 alternative vaccination strategies: (1) annual vaccination for a percentage of the elderly, (2) biannual vaccination for a percentage of the elderly, and (3) annual vaccination for all elderly and a fraction of the remaining population. We considered 5 vaccination uptake rates for each strategy and modeled the estimated costs, quality-adjusted life years, and incremental cost-effectiveness ratios (ICERs), indicating the cost-effectiveness of each scenario. RESULTS: In Singapore, annual vaccination for a proportion of elderly is largely cost-effective. However, with fixed uptake rates, partial biannual vaccination for the elderly yields a higher ICER than partial annual vaccination for the elderly, resulting in a cost-ineffective ICER. The most optimal strategy is the total vaccination of all the elderly and a proportion of individuals from other age groups, which results in a cost-saving ICER. This finding is consistent across different seasonality regimes. CONCLUSIONS: Tropical countries like Singapore can have comparably cost-effective vaccination strategies as found in countries with winter epidemics. The vaccination of all the elderly and a proportion of other age groups is the most cost-effective strategy, supporting the need for an extensive national influenza vaccination program.

Erratum to "Impact of delta variant and vaccination on SARS-CoV-2 secondary attack rate among household close contacts" [The Lancet Regional Health - Western Pacific 17 (2021) 100299].

[This corrects the article DOI: 10.1016/j.lanwpc.2021.100299.].

Cost and anonymity as factors for the effective implementation of pre-exposure prophylaxis: an observational study among gay, bisexual and other men who have sex with men in Singapore.

Background HIV pre-exposure prophylaxis (PrEP) is currently offered by several public and private clinics at unsubsidised prices in Singapore, but to date, no information is available on the effect of these services. This study sought to assess the knowledge and uptake of, and willingness to use PrEP among gay, bisexual and other men who have sex with men (GBMSM) in Singapore. METHODS: Recruitment was conducted through Grindr®, a geosocial networking application for GBMSM. Results were quantitatively analysed through descriptive statistics and multivariate Poisson regression models, while open-ended responses were qualitatively coded and categorised. RESULTS: Of the 1339 participants who responded, 1098 participants who indicated their knowledge and use of PrEP were included in the analytic sample. Overall, 15.0% (n=154) had taken PrEP, 66.2% (n=678) had heard of but not taken PrEP, while 18.8% (n=193) had never heard of PrEP. Of those who had ever taken PrEP, 59.6% (n=90) had obtained PrEP from overseas or other unofficial sources. Of those who had heard of but never taken PrEP, 73.3% (n=486) reported that they would consider taking PrEP. Those who had taken PrEP were older and had higher educational attainment. CONCLUSIONS: The gap between the willingness to use PrEP and its uptake may be attributed to the cost of PrEP and issues of anonymity at healthcare settings in Singapore. National financing schemes are needed to expand access to PrEP if it is to make a meaningful effect to the Singapore HIV/AIDS response.