Benefits of increasing the dose of influenza vaccine in residents of long‐term care facilities: A randomized placebo‐controlled trial

Abstract

Increased vaccine doses and mid-season boosting may increase the proportion of residents with protective immunity from influenza in long-term care facilities. In a multi-center study (1997-1998), 815 residents from 14 long-term care facilities were assigned at random to receive 15 or 30 microg of inactivated influenza vaccine, followed by a 15 microg booster vaccine or a placebo vaccine at Day 84. Seroresponses were re-analyzed by hemagglutination-inhibition (> or =4-fold titer increases, protective titer > or =40, geometric mean titers. Forty percent of the participants had pre-vaccination titers > or =40. At Day 25 after vaccination, this increased to 66.3% after a 15 microg dose versus 73.3% after a dose of 30 microg (P = 0.049). Participants receiving a 30 microg dose followed by a 15 microg booster showed more > or =4-fold titer increases at Day 109 (43.6% vs. 35.4%, P = 0.003) and protective titers > or =40 (74.2% vs. 64.6%, P = 0.041), compared to those receiving only a 15 microg dose. Differences were most apparent in participants with low pre-vaccination titers. Booster vaccination after an initial 15 microg dose of the vaccine did not increase the protective rate (61.9% vs. 63.9% after placebo). The number of participants needed to vaccinate to protect one additional resident by a dose of 15 microg was 4, by a dose of 30 microg 3, and 15 when using a 30 microg dose instead of 15 microg. Doubling the dose of influenza vaccine increased protection-related responses among residents of long-term care facilities, especially in those with low pre-vaccination titers.

Factors influencing the efficacy of two injections of a pandemic 2009 influenza A (H1N1) nonadjuvanted vaccine in systemic lupus erythematosus

“…Attenuated vaccines pose a risk to immunocompromised patients. More interestingly, other routes of influenza vaccine administration (e.g., transdermal inoculation by needle or patch) or more antigen per dose may also elicit a better immune response (42, 46–49) and should be well tolerated in SLE patients.…”

Vaccines for the elderly

“…Despite a general recommendation for vaccination of healthcare workers in many European countries, vaccination coverage is disappointingly low in this group [31]. Increased antigen dosage [32,33] and two‐dose schedules [34,35] gave conflicting results with regard to antibody titres and the benefit, which can be achieved by higher antigen doses and booster vaccinations, seems to depend on the specific vaccinee cohort and on the timing of booster intervals. These limitations need to be kept in mind for further studies.…”

Absence of Influenza A(H1N1) During Seasonal and Pandemic Seasons in a Sentinel Nursing Home Surveillance Network in the Netherlands

“…R esidents of long-term care facilities, particularly nursing homes (NHs), are among the most vulnerable to influenza because of the high prevalence of underlying chronic illnesses, 1 age-related immunosenescence, [2][3][4] the closed environment typical for this population, suboptimal antiviral strategies, 5 suboptimal vaccination responses, 6 and transmission of the virus through their caregivers. 7,8 As a result, influenza morbidity and mortality in NH residents is substantial, and case-fatality rates often exceed 5%.…”