Assignment 2

Etudes

Assignment 2: Influenza Vaccines
Michelle M. Lingaolingao
COH 603 Public Health Biology
09 October 2018
Professor Patric Schiltz
Assignment 2: Influenza Vaccines
The main goal of vaccines is to prepare a person’s immune system to defend against infectious diseases. In order to do this vaccines are an intentionally administered to gain exposure to the infectious agent. This confers protection immunity against possible infection and protects those who are vulnerable. In other words, vaccines trigger an immune response that results in protection against infectious diseases, such as Influenza. Having a healthy immune system is essential to health and well-being.

Vaccines and immunity allow better capability to cope with toxic agents. Immunity protects the body against infectious diseases mainly through the production of specialized protein molecules, known as “antibodies” or “immunoglobulins,” once the immune system has been stimulated by the presence of foreign substances, called “antigens,” from, for example, pathogens or vaccines (Center for Disease Control and Prevention, 2015b; Siegrist, 2008). A vaccine must produce high quality antibodies to safeguard and decrease the incidence of infectious diseases. Vaccines vary in that some have the ability to generate an immunologic memory from a natural infection. Other vaccines may need the assistance of boosters for people to remain immune.
Live attenuated and inactivated are two distinctive types of vaccines. Vaccines containing live, attenuated antigens confer a stronger immune response because the antigen is more similar to that encountered during natural infection; however, in rare cases, the virus may replicate uncontrollably in immunocompromised individuals and lead to a severe or fatal reaction (Cox, 2004). In an inactivated vaccine, the virus or bacterium is not alive and is not able to cause an infectious disease through unintended replication (Cox, 2004). There are three types of influenza, Type A, B and C. Currently there are two types of influenza vaccine are available in the United States, inactivated influenza vaccine (IIV) and live attenuated influenza vaccine (LAIV).
The IIV and the LAIV both contain type A (H1N1), type A (H3N2), and type B influenza. The LAIV varies from the IIV for reasons such as, its intranasal administration and its ability to replicate the nasal mucosa. Additionally, the LAIV is only given to healthy, non-pregnant persons 2 through 49 years of age (Center for Disease Control and Prevention, 2015a). The influenza vaccines available in the United States are the Trivalent (IIV3), Quardrivalent (IIV4), Quardrivalent (LAIV4), and one recombinant influenza vaccine-Trivalent (RIV3). Yearly recommendations are issued to stay up to date with the influenza virus and vaccinations.

According to the American Academy of Family Physicians, one recommendation was to reinstate the use of the quardrivalent live attenuated influenza vaccine LAIV4, commonly known as the Flu Mist (Crawford, 2018). The Flu Mist confers prevention of influenza disease caused by influenza A subtype viruses and type B viruses. The formulation for the Flu Mist includes four vaccine virus strains: an A/H1N1 strain, an A/H3N2 strain and two B strains (FDA, 2018). The B strains consist of both the B/Yamagata/16/88 and the B/Victoria/2/87 lineages (FDA, 2018). Other inactive ingredients are monosodium glutamate, gelatin, arginine, sucrose, dibasic potassium phosphate, monobasic potassium phosphate, and gentamicin (FDA, 2018).
The IIV has been available for 78 years and often preferred due to its long stance in health history yet, research has revealed that the duration of immunity following inactivated influenza vaccination is less than 1 year because of waning of vaccine-induced antibody and antigenic drift of circulating influenza viruses (Center for Disease Control and Prevention, 2015a). The IIV are standard-dose, unadjuvanted, inactivated influenza vaccines available in quadrivalent (IIV4) and trivalent (IIV3) formulations and recombinant influenza vaccine available in a quadrivalent formulation (RIV4; FluBlok Quadrivalent) (Crawford, 2018). The specific formulation for the IIV3 includes the A/H1N1 strain, an A/H3N2 strain and one B strain. The IIV4 contains four, which include two A viruses and two B viruses. As a result, the quadrivalent vaccine has a wider range of protection since it encompasses four different influenza virus strains.

The RIV4 is the only influenza vaccine that does not require an egg-grown process and does not use chicken. Instead, manufacturers isolate the hemagglutinin or “HA” gene from a naturally occurring “wild type” recommended vaccine virus and combines it with a virus that flourishes with insect cells (Center for Disease Control, 2018). This “recombinant” vaccine virus is then mixed with insect cells and allowed to replicate in these cells (Center for Disease Control, 2018). One reason the influenza vaccine changes is due to the evolution of the influenza virus. Another reason is the body’s immune response adapts to the vaccine over time.

The fact that the influenza virus constantly mutates and evades the immune response leads to decreased protection. In order to offer the best protection, annual updates to the influenza vaccine is essential. Even with annual changes, the influenza vaccine may still be behind due the time it takes to improve the vaccine and the constant evolution of the influenza virus. Upon research and review of the morbidity and mortality rates researchers are able to recommend changes to the influenza vaccine based on what will be the most common. According to such recommendation, vaccine manufacturers proceed each year with two different vaccine production campaigns in order to match the vaccine composition with global epidemiological surveillance data and so, develop each time an updated vaccine formulation (Gerdil, 2003). With each update, health care providers continue to recommend annual influenza vaccines as it reduces an individual’s chance of acquiring influenza.
References
Center for Disease Control and Prevention. (2018). How Influenza (Flu) Vaccines Are Made.
Retrieved from: https://www.cdc.gov/flu/protect/vaccine/how-fluvaccine-made.htm#recombinant
Center for Disease Control and Prevention. (2015a). Influenza. Retrieved from:
https://www.cdc.gov/vaccines/pubs/pinkbook/flu.html
Center for Disease Control and Prevention. (2015b). Principles of Vaccination: Immunology of Vaccine-Preventable Diseases. Retrieved from: https://www.cdc.gov/vaccines/pubs/pinkbook/prinvac.html
Cox, R. J., Brokstad, K. A., ; Ogra, P. L. (2004). Influenza Virus: Immunity and Vaccination
Strategies. Comparison of the Immune Response to Inactivated and Live Attenuated Influenza Vaccines. Scandinavian Journal of Immunology, 59(1), 1-15.

Crawford, C. (2018). CDC Releases Guidance for 2018-19 Influenza Season. Retrieved from: https://www.aafp.org/news/health-of-the-public/20180906seasonalflurecs.html
FDA. (2018) FluMist Quadrivalent. Retrieved from:
https://www.fda.gov/downloads/biologicsbloodvaccines/vaccines/…/ucm294307.pdf
Gerdil, C. (2003). The Annual Production Cycle for Influenza Vaccine. Vaccine, 21(16), 1776-
1779.

Siegrist, C. A. (2008). Vaccine Immunology. Vaccines, 5(1), 17-36.