Influenza Vaccination By Jessica Davies

History Vaccines are used in both humans and animals The first influenza pandemic was recorded in 1580 Known flu pandemics: 1889–90 — Asiatic (Russian) Flu, mortality rate said to be 0.75–1 death per 1000 possibly H2N2 1900 — Possibly H3N8 1918–20 – Spanish Flu, 500 million ill, at least 20– 40 million died of H1N1 1957–58 – Asian Flu, 1 to 1.5 million died of H2N2 1968–69 – Hong Kong Flu, 3/4 to 1 million died of H3N2 2009 - Swine Flu, caused by H1N1/09, 14,286 died

History In the world wide Spanish flu pandemic of 1918, "Physicians tried everything they knew, everything they had ever heard of, from the ancient art of bleeding patients, to administering oxygen, to developing new vaccines and sera Only one therapeutic measure, transfusing blood from recovered patients to new victims, showed any hint of success."

History In 1931, viral growth was discovered in embryonated hens' eggs The work was extended to growth of influenza virus by several workers. leading to the first experimental influenza vaccines. In the 1940s, the US military developed the first approved inactivated vaccines for influenza, which were used in the Second World War. Hen's eggs continued to be used to produce virus used in influenza vaccines, but manufacturers made improvements in the purity of the virus by developing improved processes to remove egg proteins and to reduce systemic reactivity of the vaccine. Recently the US FDA has approved influenza vaccines made by growing virus in cell cultures and influenza vaccines made from recombinant proteins have been approved, with plant-based influenza vaccines being tested in clinical trials.

Why Should You Get The Flu Shot? Influenza is a serious disease that can lead to hospitalization and sometimes even death. Every flu season is different, and influenza infection can affect people differently. Even healthy people can get very sick from the flu and spread it to others. Over a period of 31 seasons between 1976 and 2007, estimates of flu-associated deaths in the United States range from a low of about 3,000 to a high of about 49,000 people. During a regular flu season, about 90 percent of deaths occur in people 65 years and older.

How Do They Work? Flu vaccines (the flu shot and the nasal-spray flu vaccine) cause antibodies to develop in the body about two weeks after vaccination. These antibodies provide protection against infection with the viruses that are in the vaccine. The seasonal flu vaccine protects against three influenza viruses that research indicates will be most common during the upcoming season. Three kinds commonly circulate among people today: influenza B viruses, influenza A (H1N1) viruses, and influenza A (H3N2) viruses. Each year, one flu virus of each kind is used to produce seasonal influenza vaccine.

Types of Vaccines The “flu shot” — an inactivated vaccine (containing killed virus) that is given with a needle, usually in the arm. The flu shot is approved for use in people older than 6 months, including healthy people and people with chronic medical conditions. There are three different flu shots available: a regular flu shot approved for people ages 6 months and older a high-dose flu shot approved for people 65 and older an intradermal flu shot approved for people 18 to 64 years of age.

Types of Vaccines The nasal-spray flu vaccine — a vaccine made with live, weakened flu viruses that is given as a nasal spray (sometimes called LAIV for “Live Attenuated Influenza Vaccine”). The viruses in the nasal spray vaccine do not cause the flu. LAIV is approved for use in healthy people 2 through 49 years of age who are not pregnant. It takes about 2 weeks after the vaccine is given before antibodies start to develop to help protect against the virus.

Who Should Get The Vaccine? Everyone who is at least 6 months of age should get a flu vaccine. It’s especially important for some people to get vaccinated. People who are at high risk of developing serious complications like pneumonia if they get sick with the flu. Including: People who have certain medical conditions including asthma, diabetes, and chronic lung disease. Pregnant women. People 65 years and older People who live with or care for others who are high risk of developing serious complications. Including: household contacts and caregivers of people with certain medical conditions including asthma, diabetes, and chronic lung disease.

Who Should Not Get The Vaccine? People who have a severe allergy to chicken eggs. People who have had a severe reaction to an influenza vaccination. Children younger than 6 months of age (influenza vaccine is not approved for this age group) People who have a moderate-to-severe illness with a fever (they should wait until they recover to get vaccinated.) People with a history of Guillain–Barré Syndrome (a severe paralytic illness, also called GBS) that occurred after receiving influenza vaccine and who are not at risk for severe illness from influenza should generally not receive vaccine.

Flu Vaccine Effectiveness The ability of flu vaccine to protect a person depends on two things: 1) the age and health status of the person getting vaccinated 2) the similarity or “match” between the virus strains in the vaccine and those circulating in the community. If the viruses in the vaccine and the influenza viruses circulating in the community are closely matched, vaccine effectiveness is higher. If they are not closely matched, vaccine effectiveness can be reduced.

Flu Vaccine Effectiveness It’s important to remember that even when the viruses are not closely matched, the vaccine can still protect many people and prevent flu-related complications. Such protection is possible because antibodies made in response to the vaccine can provide some protection (called cross-protection) against different, but related strains of influenza viruses

Vaccine Side Effects Flu Shot -Soreness, redness, or swelling where the shot was given, Fever (low grade), and Aches If these problems occur, they begin soon after the shot and usually last 1 to 2 days. Almost all people who receive influenza vaccine have no serious problems from it. However, on rare occasions, flu vaccination can cause serious problems, such as severe allergic reactions.

Vaccine Side Effects Side Effects of Nasal Spray In Children: runny nose, wheezing, headache, vomiting, muscle aches and fever In Adults: runny nose, headache, sore throat, and cough