influenza nad trivalent

Influenza is an infectious immune system disease caused by the flu virus. The illness has threatened the lives of people all over the world. Thousands of people are infected and half of them die every year from flu-related causes. Health officials across the globe have prepared annual seasonal influenza vaccine to minimize the risk of infection and the number of deaths associated with influenza. In the US, viruses spread at higher levels during flu seasons. The flu virus has spread from one person to another. The increase in the number of vaccines would eventually limit the spread of influenza among the population. Flu vaccines lessen the spread of the virus. When vaccines are administered, antibodies build up in the body two weeks from the day of vaccination. The seasonal vaccines administered to populations protect them against viruses that have been researched as most common in the upcoming flu season.
Trivalent vaccines have been used over time to prevent influenza and are meant to protect against three flu viruses; A (H1N1) influenza virus, A (H3N2) influenza virus and type B influenza virus. Research has been carried out to find out the effectiveness of the trivalent vaccine to counter the three types of infections. Results from the research showed that the efficacy of trivalent vaccine range widely from one season to the other depending on other factors such as the individual being vaccinated, the characteristics of the person regarding age and health status, and the similarity of the influenza virus and trivalent vaccine matching to prevent influenza. (Milne et al 2016).
Substantial benefits of preventing flu illness using vaccination have been recorded when there is a match between the virus and the flu vaccine. Unmatched virus and vaccine occur when research has been done, and a conclusion on the type of vaccine to be used has been determined, but the virus mutates in the body of the host leading to unmatching. According to ( Belongia., et al. 2016,) the amount of Vaccine effectiveness (VE) regarding prevention varied by the type and subtype of influenza virus. The study looked at some VE estimates from 2004 to 2015 and found that trivalent vaccine has the capability of preventing influenza at a range of 57% -65% against H1N1 AND 54% against influenza B viruses and that it was lower when the virus and the vaccine were unmatched.
A control case study of pediatric children between the ages of 6 months to 18 years old assessed the effectiveness of the trivalent vaccine in all children giving particular attention to children with asthma, which is closely associated with influenza, to prevent hospitalization. (Joshi., et al. 2012). The research was carried on both the children who had laboratory confirmation of influenza from 1999 to 2006 and those who did not. The study was to determine the efficiency of trivalent vaccination in preventing hospitalization. A higher trend of children hospitalization was observed in those previously vaccinated compared to children who had not been vaccinated with trivalent vaccine. The trivalent vaccine did not provide any prevention against hospitalization for pediatric subjects especially those with asthma. (Shinjoh, et al., 2015).
Infection with influenza virus has been recorded as the cause of severe illness and hospitalization among infants and pregnant women. Influenza can predispose the young infants to bacteria-related pneumonia. A study from Hong Kong and North America has indicated hospitalization rates among infants with flu. Fatalities related with influenza are common for children under 6 months of age. Vaccination of pregnant women with trivalent influenza vaccine has been found to be useful in the US. The study conducted revealed that maternal vaccination had significant clinical effectiveness. Laboratory proved influenza reduced illness by 63% in infants to 6 months old children after vaccination of expectant women. The use of trivalent vaccine also showed a reduction in respiratory disease and fever in mothers and infants by 36%.
Vaccination of older adults using trivalent vaccine has been effective in the prevention of influenza. Most people above the age of 65 years have underlying medical conditions which have considerably weaken their immune system. Benefits of vaccination using trivalent vaccine have managed to reduce hospitalization cases among this population. Vaccinated individuals at this risk group may be hospitalized, but the chances of influenza leading to death have been minimized. (Song et al. 2013).
Trivalent vaccine is beneficial when administered before the onset of flu. Delays in vaccination against influenza result in increased multiplication of viruses in the body, leading to the ineffectiveness of trivalent vaccine in hospitalized cases of influenza disease. Complications, e.g. pneumonia, sinuses, bronchitis, and ear infections which are mostly associated with flu affect the functioning and effectiveness of the vaccine.( Baxter, 2016) Delay in administration of the vaccine during the early stages cripples the immunity of the body leading to reduced efficacy in prevention of flu as it leads to the multiplication of viruses inside the body system. Administration of trivalent virus in the onset has succeeded in preventing cardiac and pulmonary diseases in children. (Blyth et al. 2014).
Vaccination in children done at later stages of influenza disease has failed to prevent hospitalization of children. Most children end up in the intensive care unit for the treatment a situation that should have been avoided by early vaccination. (Flannery et al 2015).
Trivalent vaccine was designed to prevent against three types of viruses. A study on the effectiveness of the vaccine has shown that there is a reduced effectiveness in control of A (H3N2) compared to H1N1 and B viruses. (Centers for Disease Control and Prevention, 2013). Influenza viruses undergo frequent genetic changes. The changes occur in influenza virus A (H3N2) more frequently than other viruses resulting in the difference between the constituents of the flu vaccine and that of the virus. The time between the recommendations to users of the vaccine against H3N2 and its delivery, this type of infection undergoes changes that will affect the effectiveness of the vaccine.
Seasonal flu vaccines are mainly produced using growth in eggs. Almost all influenza viruses undergoes growth changes during production .antigenic changes is exhibited more in A(H3N2) virus compared to other types of influenza viruses. The rapid antigenic changes observed in this kind of virus reduce the capability of the trivalent vaccine to efficiently deal with influenza A (H3N2). The probability of the illness and the intended vaccine for seasonal vaccination to match become low with A (H3N2) influenza virus. Un-matching between the vaccine and the virus reduces the effectiveness of trivalent vaccine Cai, et al. 2017).Challenges in obtaining the right and effective vaccine have been affected by the mutation of viruses making trivalent vaccine effective differently with strains of viruses.
Conclusion
Vaccination is considered to be the most effective way of preventing influenza. Trivalent and quadrivalent vaccines have been developed to avoid the influenza viruses. Several studies and research have been done to determine the effectiveness of the trivalent vaccine in preventing influenza. The vaccine has been considered in order to avoid influenza in expectant mothers. Reduction in deaths caused by influenza diseases among the elderly has been reduced using the trivalent vaccine. The vaccine has been effective in preventing the child against the influenza virus. The vaccine effectiveness has been affected by the marching of the vaccine and the virus during administration; success and effectiveness have been recorded when there is a match between the virus and the vaccine.
The trivalent vaccine is effective when administered before the outbreak of the flu or during the early stages of influenza diseases. The vaccination done during hospitalization or late stages of influenza disease has shown reduced effectiveness. The trivalent vaccine works well with the B strain of influenza viruses and H1N1 but shows reduced efficiency with the H3N2 type of infection which undergoes frequent genetic changes.

References
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Song, J. Y., Cheong, H. J., Noh, J. Y., Seo, Y. B., Choi, W. S., Cho, G. J., … & Kim, W. J. (2013). Long‐term and cross‐reactive immunogenicity of inactivated trivalent influenza vaccine in the elderly: MF59‐adjuvanted vaccine versus unadjuvanted vaccine. Journal of medical virology, 85(9), 1591-1597.