WHAT IS VACCINE AND WHY IT IS IMPORTANT:
An administration of antigenic substance produced from the causative agent of a disease or a synthetic substitute, used to trigger immunity to a pathogen.
Vaccines were first developed in the 18th century, they have been in used to fight many deadly disease and illnesses. And despite of some failure, vaccines have been widely in used by the scientists for some research and public health concerns as one of the greatest medical achievement and breakthroughs of the modern era. Vaccines can only reach their full potential if at least enough people are vaccinated to stop the spreading of dangerous pathogens in the society. Vaccines mode of action is using the weakened pathogen enough to trigger but not causing a disease in such a way that body starts to develop an immunity against that particular pathogen. The mechanism through which the body develops the immunity keep a track of that disease for the future benefit that if in case that person may get in contact with that particular disease again . This process of combating and keeping a track is very different from the drug action as it keep the track unlike in drugs mode of action.
There are 2 reasons and factors accounted for vaccine failures, the first cause is about the failure related to vaccine is in vaccine attenuation, vaccine storage, its administration, vaccine reconstitution and its maintenance. The other factor is related to the host in which host genetics, its immune status, age, health status show relevancy to the causes of vaccine failure.
Followings are the number of causes associated to the vaccine failure.
1. POOR MAINTENANCE AND VACCINE ADMINISTRATION
This is the most common cause of vaccine failure in routine uses of vaccines. This might be due to transportation, failure of electricity or refrigerators, its failure in storage, prolonged exposure to sunlight, temperature fluctuations outside the normal range and reconstitution of too much vaccine.
2. HOST FACTOR
Host factor is the factor typically related to the person genetics. The major histocompatibility complex varies from host to host and its structure dictates how will a host respond to an antigen.
3. MATERNAL ANTIBODIES
Maternal antibodies are transferred from the mother through the placenta and through colostrum. The first milk the newborns receive. Antibodies are small protein to be called B cell receptors . These antibodies with a foreign particles to help destroy and kill them. High levels of these antibodies are present in newborn’s bloodstream which will ultimately block the effectiveness of a vaccine.
4. DIFFERENT STRAINS
Vaccines have specific strains of antigen like virus or bacteria that causes illnesses. A vaccine produced from one strain may not protect against another strain. As an example, some vaccines against leptospirosis only protect against two types of the bacteria, while others protect against four different types.
5. DAMAGED VACCINE
A very rare happening, but it can be happen if the vaccine exposed to ultraviolet light, if there is a prolonged period between when it was reconstituted and when it was used. If not handled carely, it can happen that a modified live vaccine could be inactivated.
6. UNSCHEDULE VACCINATION
It includes VACCINE INTERFERENCE and PROLONGED INTERVAL BETWEEN VACCINATIONS in which time elapses of short or long period between doses of vaccines can lead to vaccine interference can occur. Because the immune system is no longer induces primary response and less of an immune response may or a delayed vaccination result into triggering a secondary immune response.
To trigger an immune response it must be noted that a host immune system should functioning adequately or is suppressed as it provides protection from a vaccine, a host immune system must be adequately stimulated by the vaccine.
8. VACCINE REACTIONS
Different vaccines induces different vaccine reactions which occur within different time period. For example
-Pronounced redness and swelling at the site of injection.
-Severe head or neck pain.
-Joint pain and disabling fatigue.
Adverse effects includes
-Paralysis of any part of body.
-Chronic respiratory problems.
-Excessive bruising or bleeding.
And other serious complications.
9. EXPIRED VACCINE
Most common cause is the expired in storage, less shelf life and the manufacturer only with few months in hand.
10. VACCINE ADMINISTRATION
Vaccine administration includes the criteria of dosage, Needle hygiene and its management and the improper mixing of diluents in vaccine.
11. VACCINATION UNDER HIGH TEMPERATURE
Don’t vaccinate under high temperature. Vaccination should be done during the cooler periods of the day. Heat sources in brooder houses may be temporarily turned off. Vaccinate under 30 degrees.
12. ANY PHYSIOLOGICAL STRESS
Any agent which disrupts the physiological and psychological stability of a host is stressor .An animal vaccinated under stress, there are chances that it may fail.
From time to time, vaccination will fail. Although there are other factors to be blamed, need to be considered. Vaccines are considered to be a life insurance. Most people have life insurance. Likewise, in a poultry operation, the need is a disease prevention. However, if a breakdown or loop in the biosecurity is breached a disease outbreak occurs, the vaccination program should be initiates with precautions and effective to limit resulting losses. A thorough understanding and a study of the causes of vaccine failure will help prevent such losses in the future.