Safety and Efficacy of Intradermal Trivalent Influenza Vaccination in Institutionalized Older Adults
Status:
Unknown status
Trial end date:
2015-06-01
Target enrollment:
Participant gender:
Summary
Influenza is associated with significant morbidity and mortality. Institutionalized older
adults (age>65) is the group associated with highest risk of complications. Influenza
vaccines are the cornerstone of influenza prevention but one systematic review has found that
there is no statistically significant difference against laboratory confirmed influenza. A
major reason is immune senescence in older adults which result in weaker response towards
vaccines when compared with young adults. Intradermal administration of vaccine has been
suggested to improve immune response due to the abundance of immunostimulatory cells, such as
dendritic cells in the dermis. Intradermal administration of influenza vaccine has been shown
to have comparable or superior efficacy compared with intramuscular administration in the
>60-year old population and the rates of adverse events post-vaccination were also comparable
between them. The immunogenicity of intradermal administration has also been shown to be
better in immunocompromised patients, including community dwelling older adults. In addition,
intradermal vaccination has good acceptability and safety profile in different countries, so
it has been licensed in Hong Kong and worldwide. However, there is little study regarding the
efficacy of intradermal vaccination of influenza in institutionalized older adults,
investigators therefore would like to perform a prospective, randomized study to compare the
safety and immunogenicity between conventional full dose intramuscular immunization and full
dose intradermal immunization of the trivalent influenza vaccine in institutionalized older
adults.
The hypothesis is that full dose intradermal trivalent influenza vaccination is as effective
as full-dose standard intramuscular injection in terms of seroconversion and seroprotection
rate in institutionalized older adults. Finding of this study will be important in the
vaccination of institutionalized older adults and immunocompromised patients as intradermal
vaccine may induce a better immune response against influenza infection.