Influenza primary prevention
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Overview
Influenza, commonly known as flu, is an infectious disease of birds and mammals caused by RNA viruses of the biological family Orthomyxoviridae (the influenza viruses). In humans, common symptoms of influenza infection are fever, sore throat, muscle pains, severe headache, coughing, weakness and general discomfort.
Primary Prevention
Vaccination and infection control
Vaccination against influenza with a flu vaccine is strongly recommended for high-risk groups, such as children and the elderly.
Flu vaccines can be produced in several ways; the most common method is to grow the virus in fertilised hen eggs. After purification, the virus is inactivated (for example, by treatment with detergent) to produce an inactivated-virus vaccine. Alternatively, the virus can be grown in eggs until it loses virulence and the avirulent virus given as a live vaccine.[1] The effectiveness of these flu vaccines is variable. Due to the high mutation rate of the virus, a particular flu vaccine usually confers protection for no more than a few years. Every year, the World Health Organization predicts which strains of the virus are most likely to be circulating in the next year, allowing pharmaceutical companies to develop vaccines that will provide the best immunity against these strains.[2] Vaccines have also been developed to protect poultry from avian influenza. These vaccines can be effective against multiple strains and are used either as part of a preventative strategy, or combined with culling in attempts to eradicate outbreaks.[3]
It is possible to get vaccinated and still get influenza. The vaccine is reformulated each season for a few specific flu strains, but cannot possibly include all the strains actively infecting people in the world for that season. It takes about six months for the manufacturers to formulate and produce the millions of doses required to deal with the seasonal epidemics; occasionally, a new or overlooked strain becomes prominent during that time and infects people although they have been vaccinated (as by the H3N2 Fujian flu in the 2003–2004 flu season).[4] It is also possible to get infected just before vaccination and get sick with the very strain that the vaccine is supposed to prevent, as the vaccine takes about two weeks to become effective.[5]
The 2006–2007 season is the first in which the CDC has recommended that children younger than 59 months receive the annual flu vaccine.[6] Vaccines can cause the immune system to react as if the body were actually being infected, and general infection symptoms (many cold and flu symptoms are just general infection symptoms) can appear, though these symptoms are usually not as severe or long-lasting as influenza. The most dangerous side-effect is a severe allergic reaction to either the virus material itself, or residues from the hen eggs used to grow the influenza; however, these reactions are extremely rare.[7]
Good personal health and hygiene habits are reasonably effective in avoiding and minimizing influenza. People who contract influenza are most infective between the second and third days after infection and infectivity lasts for around 10 days.[8] Children are notably more infectious than adults, and shed virus from just before they develop symptoms until 2 weeks after infection.[8][9]
Since influenza spreads through aerosols and contact with contaminated surfaces, it is important to persuade people to cover their mouths while sneezing and to wash their hands regularly.[6] Surface sanitizing is recommended in areas where influenza may be present on surfaces.[10] Alcohol is an effective sanitizer against influenza viruses, while quaternary ammonium compounds can be used with alcohol, to increase the duration of the sanitizing action.[11] In hospitals, quaternary ammonium compounds and halogen-releasing agents such as sodium hypochlorite are commonly used to sanitize rooms or equipment that have been occupied by patients with influenza symptoms.[11] During past pandemics, closing schools, churches and theaters slowed the spread of the virus but did not have a large effect on the overall death rate.[12][13]
References
- ↑
- ↑
- ↑ Capua, I (2006). "The challenge of avian influenza to the veterinary community" (PDF). Avian Pathol. 35 (3): 189–205. PMID 16753610. Unknown parameter
|coauthors=ignored (help) - ↑ Holmes, E (2005). "Whole-genome analysis of human influenza A virus reveals multiple persistent lineages and reassortment among recent H3N2 viruses". PLoS Biol. 3 (9): e300. PMID 16026181. Unknown parameter
|coauthors=ignored (help) - ↑
- ↑ 6.0 6.1 Prevention and Control of Influenza: Recommendations of the Advisory Committee on Immunization Practices (ACIP) CDC report (MMWR 2006 Jul 28;55(RR10):1–42) accessed 19 Oct 2006.
- ↑ Questions & Answers: Flu Shot CDC publication updated Jul 24, 2006. Accessed 19 Oct 06.
- ↑ 8.0 8.1 Carrat F, Luong J, Lao H, Sallé A, Lajaunie C, Wackernagel H. "A 'small-world-like' model for comparing interventions aimed at preventing and controlling influenza pandemics". BMC Med. 4: 26. PMID 17059593.
- ↑ Mitamura K, Sugaya N (2006). "[Diagnosis and Treatment of influenza—clinical investigation on viral shedding in children with influenza]". Uirusu. 56 (1): 109–16. PMID 17038819.
- ↑ Hota B (2004). "Contamination, disinfection, and cross-colonization: are hospital surfaces reservoirs for nosocomial infection?". Clin Infect Dis. 39 (8): 1182–9. PMID 15486843.
- ↑ 11.0 11.1 McDonnell G, Russell A (1999). "Antiseptics and disinfectants: activity, action, and resistance". Clin Microbiol Rev. 12 (1): 147–79. PMID 9880479.
- ↑ Hatchett RJ, Mecher CE, Lipsitch M (2007). "Public health interventions and epidemic intensity during the 1918 influenza pandemic". Proc Natl Acad Sci U S A. 104 (18): 7582–7587. PMID 17416679.
- ↑ Bootsma MC, Ferguson NM (2007). "The effect of public health measures on the 1918 influenza pandemic in U.S. cities". Proc Natl Acad Sci U S A. 104 (18): 7588–7593. PMID 17416677.