What Is a Vaccine? - Medical Essay

A vaccine is a biological preparation used in the prevention of an infection. Vaccines prepare the bodys immune system against a specific infectious agent for which they are prepared. The immune system of the human body is designed to identify foreign antigens and mount an immune response against them. It is particularly efficient in distinguishing between self and non-self, and it only fights off the latter. However, the immune reaction takes days to weeks to prepare immune mediators to the levels required to fight an invading microorganism. Therefore, a person can become very sick before the body recruits the biological mediators enough to kill a microorganism. The period also gives the organism time to accumulate in the body in numbers that are sufficient to cause a full blown disease that is fatal for an individual. Vaccines, therefore, prepare the body to fight a specific infection in advance (www.health.gov.au).

Biology behind the vaccine

There are different classes of vaccines. The type of vaccine to apply depends on the biological nature of the organism, the target immunity, and the virulence of the organism. Each class of vaccines has its mode of production. The vaccine types include live attenuated, killed vaccines, vector vaccines, and DNA vaccines. Live attenuated vaccines are made from a weakened form of microorganism. The weakening of this organism is achieved through heating at very high temperature or exposure to chemicals. The vaccine is injected into a healthy individual. The immune system recognizes the altered organism, makes antibodies and primes antibody producing cells. However, the changed form of the organism does not make a person sick, and its eventually cleared off from the body. An example of a live attenuated vaccine is oral Polio Vaccine. Killed vaccines, on the other hand, are administered as inactivated microorganisms that do not have their natural shape. However, the microorganism has its associated epitopes that the immune system recognizes as foreign antigens. DNA and vector vaccines work hand in hand. A DNA segment from an organism is inserted into a vector that transports it into the body cells. Through the cells transcription and translation mechanisms, microorganisms proteins are produced and elicit an immune reaction. In this manner, the body is protected against future infections by the DNA source organism (www.health.gov.au).

Cost of vaccines

Vaccines are costly to produce, license, and distribute. The process of vaccine production requires sophisticated technology which is expensive to acquire. It also requires highly trained personnel, complicated equipment, and protected facilities. For example, culturing organisms for vaccines needs a massive input of sterile culture media that is expensive to buy. After the organisms are cultured, they are inactivated or killed in vitro using the safest method that will not render them harmful. All these activities add up to the total cost of vaccine production (www.hsa.gov.sg).

Storage and life limit

The storage life of vaccines depends on the temperature at which they are kept post-manufacture. Some vaccines require being frozen in liquid nitrogen for very low temperatures of up to -200 Centigrade. Other vaccines only need to be refrigerated at 2-8 degrees Centigrade to preserve their viability. Every vaccine has an expiry date after which it becomes either useless or harmful. However, the life limit of a vaccine depends on the storage condition. If the manufacturer indicates that a vaccine is viable for three months when kept at 4 to 10 degrees Centigrade, any deviation from the set temperature destroys the vaccine and makes it inefficient (www.historyofvaccines.org).

Vaccines trail and ethics involved

A vaccine is not safe for human use before it goes through various trail phases. Although there are strict regulations that govern the first and second phases of vaccine trails on non-human subjects, trails on a human being is a more serious ethical issue. The manufacturer must provide evidence that the previous trail phases have not adversely affected experimental animals. They must be able to prove that there are specific doses that are not toxic to human beings. The human subjects undertaking the trial must consent to the involvement in the study. Additionally, the manufacturer must avoid using vulnerable populations like the mentally unfit or prisoners to test vaccines (www.historyofvaccines.org)

Gender and age issues

Vaccine administration depends on the age, gender and the health status of an individual. For instance, it is not safe to give live vaccines to immune-compromised individuals. There are vaccine regimes that are given early in life to protect children from respective infectious diseases. Some vaccines like Human Papilloma Virus (HPV) are only given to women who are at the risk of getting cervical cancer from the HPV virus. Therefore, its the role of the government to sensitize the people on the use of vaccines and stock public health centers with appropriate vaccines to achieve the benefits of immunization (www2.health.vic.gov.au).Conclusion

In conclusion, vaccines keep the body ready to fight off infections caused by a plethora of bacteria and viruses. There are various classes of vaccines that suit different categories of people. Due to the biological nature, vaccines are prone to destruction and should be stored and used as per the manufacturers guidelines. Vaccines are costly to produce, and the government should set adequate funds to acquire them from reputable manufacturers for the greater good of the population.

References

http://www.health.gov.au/internet/main/publishing.nsf/content/cda-pubs-cdi-2002-cdi26suppl-vpd99_00.htm/$FILE/vpd99_00.pdf

https://www2.health.vic.gov.au/public-health/immunisation/immunisation-schedule-vaccine-eligibility-criteria/vaccine-history-timeline

https://www.historyofvaccines.org/content/articles/ethical-issues-and-vaccines

http://www.hsa.gov.sg/content/hsa/en/Health_Products_Regulation/Consumer_Information/Public_Advisories/Influenza_A_H1N1_information/H1N1_Vaccines/understanding-vaccines--vaccine-development-and-production.html