Protecting The Elderly From Seasonal Flu

Elderly patients could benefit from pretreatment with imiquimod before seasonal influenza vaccination.

AsianScientist (Aug. 4, 2014) – Scientists have found that treating elderly patients with imiquimod before immunizing them against influenza improved the protective effects of the vaccine. This study has been published in the journal Clinical Infectious Diseases.

Every year, many elderly patients are hospitalized for influenza infection and its complications, even though ten percent were immunized with the conventional intramuscular seasonal influenza vaccination. This breakdown in protection is often attributed to the the lower level of protective antibodies in elderly patients six months after immunization. In particular, elderly patients with medical comorbidities are particularly vulnerable to the summer influenza peak, or just before the next annual vaccination.

In the present study, a team led by Professor Yuen Kwok-yung, Chair Professor of Department of Microbiology, Li Ka Shing Faculty of Medicine of The University of Hong Kong (HKU) has discovered a simple and practical way of protecting elderly patients with medical illness from seasonal influenza. By applying the Toll-like receptor 7 agonist imiquimod before intradermal injection, the protection by flu vaccine is enhanced, thus decreasing the risk of hospitalization. Imiquimod is a safe immune-stimulatory drug, which has used topically to treat skin warts for many years.

A total of 91 Chinese subjects were enrolled in the double blind randomized controlled trial, with a median age of 73 years. Thirty subjects received topical imiquimod pretreatment followed by intradermal influenza vaccination, while another 30 subjects received the inactive aqueous cream followed by intramuscular influenza vaccination and 31 subjects received the inactive aqueous cream followed by intradermal influenza vaccination.

Pretreatment with topical imiquimod was shown to enhance the protective effect of influenza vaccination. The antibody production appeared two weeks earlier than in the control group and was sustained for at least one year. The vaccine recipients had only minor self-limiting adverse effects but were less often hospitalized for influenza or pneumonia.

Lead author, Professor Yuen Kwok-yung, Henry Fok Professor in Infectious Diseases and Chair Professor of Department of Microbiology, Li Ka Shing Faculty of Medicine of HKU said “We found that our new vaccination method can hasten, enhance and prolong the protective effect of the influenza vaccine, giving the elderly patients with comorbidities better protection against flu.”

The article can be found at: Hung et al. (2014) Immunogenicity of Intradermal Trivalent Influenza Vaccine with Topical Imiquimod, a Double Blind Randomized Controlled Trial.


Source: University of Hong Kong; Photo: Christian Kadluba/Flickr/CC.
Disclaimer: This article does not necessarily reflect the views of AsianScientist or its staff.

Asian Scientist Magazine is an award-winning science and technology magazine that highlights R&D news stories from Asia to a global audience. The magazine is published by Singapore-headquartered Wildtype Media Group.

Related Stories from Asian Scientist