Waaiz Alam Saad
Freshman
School of Life Sciences
Independent University, Bangladesh
April 13th, 2017
Influenza, which is often referred to as the "flu", is a viral respiratory disease which can cause severe complications and can even lead to death. Every year the influenza outbreak can seriously affect the population. The threat is especially high for children younger than 2 years, adults aged 50 years or older, pregnant women and also people with medical conditions. The virus has the ability to spread rapidly between workplaces, homes, businesses and schools. Infection can result from inhalation of infected air, direct contact or by coming in contact with contaminated objects.
According to WHO, influenza occurs globally with an annual strike rate estimated at 5%-10% in adults and 20%-30% in children. Therefore, the best method to reduce chances of getting infected is to get vaccinated annually. The vaccine is a biological preparation which contains a dead or weakened strain of a pathogen or its toxin. The body produces defensive proteins called antibodies, which recognize and kill pathogens based on antigens (unique proteins or other molecules) found on or within the pathogen. The body retains memory of the pathogen, and is able to produce antibodies against the actual live pathogen if or when it is encountered.
Each year, new vaccines need to be developed for influenza because these viruses are continuously changing and evolving. There are proteins on the surface of the virus called hemagglutinin (HA) and neuraminidase (NA). Our immune system identifies these proteins that are on the viral surface, and generates and produces antibodies against these proteins. The structures of the viral proteins are determined by genes. The genetic code of influenza changes or mutates frequently as it is very prone to copying errors when the viruses reproduce. If, for instance, there is a change in the gene encoding the HA protein, HA might change shape, and then antibodies that normally bind to the previous version of HA will no longer be able to. This would allow the newly mutated virus to evade the immune system. Mistakes or mutations occur randomly, so these changes occur slowly over time in a process known as antigenic drift. The consequence of this is that the virus eventually evolves resistance to any antibody that is common in a population.
Finding the ideal vaccine formula is therefore difficult. Vaccines are developed after careful surveillance and prediction of which strains will be common, and be likely to have an adverse impact, in the next year. Since the virus mutates rapidly, the effectiveness of vaccines can vary; they have been shown to decrease the danger of flu by about 50% to 60% among the overall population during times when most current flu viruses are same as the vaccine viruses. That may not seem like a lot, but if large percentage of the general population is protected by the vaccine, vulnerable individuals are less likely to come into intact with infected individuals. Vaccination therefore protects not only the vaccinated individual, but also others in the population; this is known as herd immunity. This is especially important for individuals who are at higher risk of acquiring severe flu, such as children, the aged, and people with certain chronic health conditions.
Saad is a Freshman at the School of Life Sciences. He plans to work in drug and vaccine development, and towards the improvement of diagnostic tools for infectious diseases.
Freshman
School of Life Sciences
Independent University, Bangladesh
April 13th, 2017
Influenza, which is often referred to as the "flu", is a viral respiratory disease which can cause severe complications and can even lead to death. Every year the influenza outbreak can seriously affect the population. The threat is especially high for children younger than 2 years, adults aged 50 years or older, pregnant women and also people with medical conditions. The virus has the ability to spread rapidly between workplaces, homes, businesses and schools. Infection can result from inhalation of infected air, direct contact or by coming in contact with contaminated objects.
According to WHO, influenza occurs globally with an annual strike rate estimated at 5%-10% in adults and 20%-30% in children. Therefore, the best method to reduce chances of getting infected is to get vaccinated annually. The vaccine is a biological preparation which contains a dead or weakened strain of a pathogen or its toxin. The body produces defensive proteins called antibodies, which recognize and kill pathogens based on antigens (unique proteins or other molecules) found on or within the pathogen. The body retains memory of the pathogen, and is able to produce antibodies against the actual live pathogen if or when it is encountered.
Mortality from seasonal influenza and pneumonia, a common secondary infection from the flu, 2010-14. CDC
Finding the ideal vaccine formula is therefore difficult. Vaccines are developed after careful surveillance and prediction of which strains will be common, and be likely to have an adverse impact, in the next year. Since the virus mutates rapidly, the effectiveness of vaccines can vary; they have been shown to decrease the danger of flu by about 50% to 60% among the overall population during times when most current flu viruses are same as the vaccine viruses. That may not seem like a lot, but if large percentage of the general population is protected by the vaccine, vulnerable individuals are less likely to come into intact with infected individuals. Vaccination therefore protects not only the vaccinated individual, but also others in the population; this is known as herd immunity. This is especially important for individuals who are at higher risk of acquiring severe flu, such as children, the aged, and people with certain chronic health conditions.
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