Estimating the burden of and impact of prevention measures against three common infectious diseases in Mainland China and Hong Kong : HFMD, RSV and influenza

Abstract

Despite the efforts and advances in infectious diseases prevention and control, the health and economic burden of some common infectious diseases in mainland China and Hong Kong Special Administrative Region, as well as the need for better approaches to prevention and control, are major concerns for mitigating and preventing their spread. This is particularly true for hand, foot and mouth disease (HFMD), respiratory syncytial virus (RSV) infections and seasonal influenza, which have been persisting and causing a significant burden in mainland China and Hong Kong.

Enterovirus 71 (EV71) and coxsackievirus A16 (CA16) are the two major viruses causing HFMD in mainland China. A comparative cost-effectiveness analysis (CEA) was conducted to investigate the marginal value of a bivalent EV71 and CA16 vaccine versus monovalent EV71 vaccines. Threshold vaccine cost (TVC), defined as the maximum additional costs of a cost-effective bivalent EV71 and CA16 vaccine beyond a monovalent EV71 vaccine, was used as the primary outcome. It was shown that with a suitable price, a bivalent EV71 and CA16 vaccine could be more cost-effective than monovalent EV71 vaccines. This analysis provides further evidence for maximising the benefit of paediatric HFMD vaccination in mainland China.

RSV is the most prevalent viral cause of morbidity and mortality attributable to acute lower respiratory infection (ALRI) among children under five years worldwide. In view of the recent promising results from the clinical trials of monoclonal antibody (mAb) candidate nirsevimab and maternal vaccine candidate ResVax for RSV prevention, new preventive interventions will likely debut within the next few years. CEA was conducted for the administration of maternal immunisation, infant mAb and paediatric immunisation as well as their combinations in eight Chinese cities using no intervention (the status quo) as the comparator. Threshold strategy cost (TSC), defined as the maximum cost that could be paid for a cost-effective preventive strategy per child, was estimated. Emerging novel interventions for paediatric RSV-ALRI prevention in China could be cost-effective if their prices are suitable. For preventive interventions with relatively shorter protection duration (namely maternal immunisation and infant mAb), administering these interventions to optimally selected monthly birth cohorts could be more cost-effective compared to their year-round counterparts. RSV seasonality is a strong determinant of such optimal timing.

Although seasonal influenza has been increasingly recognised as a trigger of acute cardiovascular deaths, no study in Hong Kong has quantified the excess burden of influenza-associated acute cardiovascular deaths, such as out-of-hospital cardiac death (OHCD). Negative binomial regression analyses were performed to investigate the association of seasonal influenza and age- and cause-specific OHCD. Seasonal influenza activity was shown to be a significant risk factor for OHCDs for all age groups and all etiologies in Hong Kong. Prevention measures against influenza infection, such as improved uptake of influenza vaccination, might potentially reduce the healthcare burden of OHCD beyond the control of cardiovascular risk factors.