Authors' objectives: To assess the efficacy or effectiveness, safety, organisational and societal issues as well as financial implication of influenza vaccination in the elderly population.

Authors' results and conclusions: Effectiveness: Influenza rate: There was good level of retrievable evidence to suggest that influenza vaccination was effective in reducing influenza rate in the elderly. The evidence showed vaccinated elderly experienced less influenza compared to placebo. The IVE ranged from 31% to 58% depending on the types of influenza viruses. Influenza like-illness (ILI): There was good level of retrievable evidence to suggest that vaccinated elderly experienced less ILI compared with unvaccinated elderly with IVE ranged from 19% to 45% among older patients aged ≥65 years old. The influenza vaccination also prevented ILI in type 1 and type 2 diabetic patients with IVE of 13%. Mortality: All-cause mortality: There was fair to good level of retrievable evidence to suggest that influenza vaccination reduced all-cause mortality with IVE of 38%- 56% among diabetic patients. Influenza-related mortality: There was fair to good level of retrievable evidence to suggest vaccination reduce mortality following hospitalisation for pneumonia and influenza by 47% with IVE 25-62%. Study in US on seasonal-influenza, stated about 88.9% influenza-associated deaths averted among vaccinated group in the elderly while among French elderly population, showed that vaccination would avoid an influenza-attributable death with IVE of 35% compared to unvaccinated group. Immune response (immunogenicity): There was fair to good level of retrievable evidence to suggest better immune response for all types of vaccine which include non-adjuvanted vaccine, aluminium hydroxide adjuvanted vaccine, and AS03A-adjuvanted vaccine. Organisational: The WHO recommended that northern hemisphere (including Malaysia) influenza season should use both trivalent or quadrivalent vaccines that contain both influenza type A and influenza type B virus (B/Colorado/06/2017-like virus of the B/Victoria/2/87-lineage) with a 75% vaccination coverage. In Malaysia, healthcare workers were included in annual immunization programme. According to Influenza Surveillance Programme in Malaysia, both National Public Health Laboratory (NPHL) Sungai Buloh and the Institute of Medical Research (IMR) found that influenza A virus was the most dominantly isolated virus with 291 (59.03%) positive isolates followed by influenza B with 202 (40.97%) isolates. However, data were not stratified according to age groups. Safety: There was limited good level of retrievable evidence to suggest that the use of influenza vaccine was associated with non-significant adverse effects such as fever and nausea. The recent report regarding influenza-related death in South Korea was associated with the certain product brand for QIV. Cost-effectiveness: Systematic review on cost-effectiveness studies showing varying results ranging from being cost-effectiveness to not cost-effective in different population groups and countries. A cost-effectiveness study using societal perspective conducted in Singapore found the elderly plus some other age groups population to be the most cost-effective strategy. Financial implication: Local economic evaluation cannot be conducted due to limitation of local data (epidemiological and costs data). Hence, the cost-effectiveness of influenza vaccination among elderly population in Malaysia cannot be determined. Based on the financial implication analysis, the use of TIV (lowest cost) as an annual influenza vaccination is estimated to have an economic implication of approximately RM5.447 million for a starting coverage rate of 10% (strategy 1). While in strategy 2, the lowest cost estimated for a coverage rate of 25% was RM13.619 million per year. For strategy 3, the estimated lowest cost of TIV for elderly with diabetes mellitus with a prevalence of 41.5% a year was RM22.61 million per year.

Authors' recommendations: Based on the review, annual vaccination may be offered for the elderly population. However, delivering annual vaccination to this group requires considerable ongoing investment. Thus, it is suggested to prioritise the vaccination to elderly with comorbidities.

Authors' methods: The following electronic databases were searched through the Ovid interface: Ovid MEDLINE® In-process and other Non-indexed citations and Ovid MEDLINE® 1946 to present, EBM Reviews - Cochrane Central Register of Controlled Trials - August 2019, EBM Reviews - Cochrane Database of Systematic Reviews - 2005 to August 2019, EBM Reviews - Health Technology Assessment – 4th Quarter 2018 and EBM Reviews – NHS Economic Evaluation Database 1st Quarter 2018. Searches were also run in EMBASE. PubMed and Google Scholar were used to search for additional web-based materials and information. The references of retrieved articles were scrutinised for additional articles. The last search was conducted on 23 January 2020.

Project Status: Completed

URL for project: https://www.moh.gov.my/index.php/database_stores/store_view/30?mid=609

Year Published: 2020

URL for published report: https://www.moh.gov.my/index.php/database_stores/store_view_page/30/346

Requestor: Ministry of Health

English language abstract: An English language summary is available

Publication Type: Mini HTA

Country: Malaysia

Organisation Name: Malaysian Health Technology Assessment

Contact Address: Malaysian Health Technology Assessment Section, Ministry of Health Malaysia, Federal Government Administrative Centre, Level 4, Block E1, Parcel E, 62590 Putrajaya Malaysia Tel: +603 8883 1229

Contact Name: htamalaysia@moh.gov.my

Contact Email: htamalaysia@moh.gov.my

Copyright: Malaysian Health Technology Assessment Section (MaHTAS)