Inactivated influenza vaccine effectiveness

The immunostimulating activity of chitosan has also been reported. A 70% DD chitosan showed immunostimulating effects by activating macrophages and natural killer cells in rats when infected with . coli and Sendai virus (Nishimura et al., 1984). Chang et al. (2004) also reported the immune-enhancing effects of chitosan as a novel adjuvant to an inactivated influenza vaccine, and the antibody content in serum remarkably increased the antiviral defenses of mice. 

Parenteral Route. Parenteral vaccination remains the immunization method of choice for most antigens because it provides more effective immune response than do any other routes of vaccination in most cases. Every years millions of people receive inactivated influenza vaccine by parenteral administration. Subcutaneous vaccination with inactivated influenza vaccine is known to induce simultaneous immune responses in the blood and upper respiratory tract of subjects. The immune response, i.e., the increase in the number of influenza virus-specific antibody-secreting cells in peripheral blood and tonsils, increased rapidly to reach a peak within 1 week after vaccination.Parenteral vaccination of a DNA vaccine encoding glycoprotein D of herpes simplex virus type 2 resulted in systemic cellular and humoral responses. The mucosal humoral responses generated by intramuscular and intradermal vaccination were comparable with those obtained by mucosal vaccination. The DNA vaccine was able to... 

In a randomized, double-blind study, trivalent, live, attenuated, cold-adapted intranasal influenza vaccine (FluMist) has been compared with intranasal placebo plus a trivalent injected inactivated influenza vaccine (5). The 200 patients were aged 65 years and over and had chronic cardiovascular or pulmonary conditions or diabetes mellitus. During the 7 days after immunization, sore throat was reported on at least one day by significantly more of the FluMist recipients (15 versus 2%). The increased frequency of sore throat may have been attributable to direct or indirect effects of vaccine virus replication. No other symptom was associated with FluMist. These findings were consistent with evaluations of other live, attenuated, cold-adapted influenza vaccine formulations in older adults. However, further studies of the safety of FluMist are warranted. 

Barker WH, Mullooly JP. Effectiveness of inactivated influenza vaccine among non-institutionalized elderly persons. In Kendal AP, Patriarca PA, eds. Options for the control of influenza. New York Alan R. Liss, 1986 169-182. 

The potential link of formaldehyde-inactivated vaccines adjuvanted with aluminium and observed with the RSV prototype vaccines raised concerns that the influenza H5N1 pandemic formaldehyde-inactivated adjuvanted vaccine could cause an immunopathological effect. As a result, a challenge study in macaque monkeys was conducted it measured both humoral and cell-mediated immune responses and evaluated lung histopathology as an endpoint. The study concluded that there was no disease enhancement.95... 

Influenza vaccines are available as inactivated trivalent split or subunit vaccine or as a live attenuated vaccine administered in-tranasally. Though both types of influenza vaccine probably are equally effective in protection from infection, they are indicated for distinct populations and should not be considered interchangeable. 

The manufacturers advise that antivirals active against influenza such as oseltamivir and rimantadine should not be given until 2 weeks after the administration of live influenza virus vaccines, and that these vaccines should not be given until 48 hours after stopping the antiviraL This is because of the theoretical concern that these antiviral drugs will inhibit replication of live vaccine virus, and therefore reduce its effect. Note that most influenza vaccines are inactivated (split virion or surface antigen), and that these would not be expected to be affected by antivirals active against influenza. 

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