Cough and cold are very common nowadays and many people seem to think that it is a minor symptom and soon would be all right…
We experience sneezing, coughing, fever, chills, fatigue, aches, sore throat, running nose etc. These can be an indication of array of diseases of which may be are unknown to a common man.
Influenza, an air borne disease is characterized by high fever, cold, cough and even pneumonia. Each year thousands of people die from influenza and even more require hospitalization.
There are only a few approved vaccines that provide optimal protection against various viral and bacterial pathogens, since it has low immune response at mucosal surfaces such as the nasal passage.
Lymphoid structure in respiratory tract of humans called Waldeyer’s ring is an important induction site for immune responses.
Herein comes the nasal vaccine!
Recently, nasal vaccine has been a great alternative for injections. Nasal vaccination has the advantage that it elicits both local and systemic immune responses. The mucosal immune response is rapid and nasal vaccines may also cause protection in distant mucosal sites. Injected vaccines stimulate the systemic immune response, but it does not provide mucosal immune protection.
Nasal route for vaccine is very efficient for prevention of many respiratory diseases. Through nasal route it is very easy for the vaccine to reach to the lungs, bronchi, alveoli which are the major sites for the cause of various diseases.
It helps in clearance of the antigens that have been present in the respiratory tract and other sites.
However, unit-dose device for nasal delivery are likely to be too expensive and unsuitable for extensive public vaccination program.
The use of nasal vaccine abstains the discomfort and hazards associated with injection and also provides improved local immune protection and cross protection at various mucosal sites. It is important to improve distribution to the nasal mucosa, while at the same time limiting deposition outside the target sites. This balance is necessary in improving the reproducibility, safety, clinical efficacy and patient compliance of nasally delivered vaccines and potent drugs.
Chitosan-An adjuvant in nasal vaccines-
Chitosan is a cationic polysaccharide which has shown to induce significant serum IgG response and secretory IgA levels superior to those induced by parenteral administration.
High doses of antigen are required to generate even modest responses in oral delivery. In contrast in nasal delivery, along with a range of adjuvants shows potent immune responses to protect against infection.
Contraindications or Drawbacks