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Non funziona l'antinfluenzale sui bimbi: lo dice la Cochrane
Meno del 10% dei virus nel vaccino
Tratto da Vaccinetwork - www.vaccinetwork.org
La Cochrane Vaccines Field lo afferma: l'antinfluenzale nei bambini non funziona. E a pubblicarlo è la prestigiosa rivista scientifica Lancet nel numero del 26 febbraio 2005. Di seguito il testo dell'abstract e la url dove lo si può trovare. Questo illustre parere smentisce quanto sostenuto in precedenza dai Cdc di Atlanta, dall'Accademia Americana di Pediatria e dalla Public Health canadese che dal 1999 avevano raccomandato il vaccino antinfluenzale ai bimbi con meno di 2 anni. La sollecitazione a vaccinare in questo modo destò non poche perplessità e nel 2002 si poterono leggere alcuni pareri critici su Epicentro (http://www.epicentro.iss.it/focus/influenza/discussione/disc_influ.htm). Ora la Cochrane Vaccines Field ha revisionato la letteratura concludendo che non vi sono evidenze di efficacia di una simile strategia vaccinale.
Vi riportiamo, tradotta, la parte più interessante delle conclusioni:
Traduzione: L'efficacia nei bambini piccoli è completamente non provata. Al massimo può favorire nei bambini più grandi una riduzione della lunghezza delle assenze scolastiche. I risultati sollevano dubbi sulla saggezza di affrettarsi in un programma di vaccinazione estesa dei bambini senza prove adeguate che questa funzioni o sia interamente sicura. I vaccini antinfluenzali possono essere efficaci contro le forme di influenza che tipicamente rappresentano meno del 10% di tutti i casi, ma non vi è modo di predire che questo sarà il virus predominante nella stagione influenzale in arrivo.
Vi alleghiamo l'abstract e in fondo la url dove lo trovate.
Autori: Jefferson T, Smith S, Demicheli V, Harnden A, Rivetti A, Di Pietrantonj C.
Titolo: Assessment of the efficacy and effectiveness of influenza vaccines in healthy children: systematic review.
Lancet 2005; 365:773-80 (26th of February). Contact Tom Jefferson, MD, toj1@aol.com
BackgroundEach year many people are ill with acute infections of the airways. Hundreds of different germs cause these infections, but the symptoms are always the same regardless of which particular germ is doing the rounds. Real influenza viruses cause—on average—only about 10% of these infections, and the rest are commonly known as "the flu". All have the same symptoms: fever, chills, cough, stuffy nose and sometimes ear and chest infections. There is no way to distinguish real influenza from the flu unless complicated laboratory tests are carried out.
Scientists and decision makers are worried about the impact that the flu has on our lives. Recently the USA and Canada have started vaccinating children, including those aged 6 to 24 months, in the hope of reducing disease spread; admissions and visits to hospitals; deaths of elderly relatives; complications, such as ear infections and pneumonia; and absences from school and parental loss of workdays.
The review
Given the important nature of the US and Canadian decision, a group of Cochrane scientists conducted a review of the scientific evidence for the use of influenza vaccines in children. They looked at the two main types of available vaccines: those made of killed influenza viruses (inactivated) and those made out of live but tamed influenza viruses (live attenuated). The Cochrane authors looked at over a thousand studies and selected 25 high-quality clinical trials in which vaccinated children were compared with unvaccinated children. For the first time in a review of influenza vaccines, seven of the included studies came from Russia and were translated especially for the Cochrane review. The combined results of these 25 clinical trials were first reported in the British journal, The Lancet. This summer, an expanded version of this review that includes information about the safety of vaccines will appear in the Cochrane Library.
The findings
The review found that live attenuated vaccines avoided more cases of real influenza (around 80%) than inactivated vaccines (around 65%). Both types of vaccines were not very good, however, against the type of flu that afflicts the overwhelming majority each year. There was no evidence that either type of vaccine worked in children below the age of two (and, in any case, live attenuated vaccines are not legal for this age group), or prevented hospital admissions, deaths or other complications. A few small studies suggested a possible shortening of the length of school absences.
The conclusions
Vaccination of small children is wholly unproven. At best, it may benefit older children by shortening the length of school absences. The findings call into question the wisdom of rushing into an expensive vaccination programme of children without adequate proof that it will work or that it is entirely safe.
Influenza vaccines may be effective against the type of influenza that typically accounts for less than 10% of all cases, but there is no way to accurately predict that it will be the predominant virus in the upcoming flu season.
http://www.thelancet.com/journal/vol365/iss9461/abs/llan.365.9461.primary_research.32370.1
www.disinformazione.it
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