Acesta este extras dintr-un articol pe care l-am gasit prin sciencedirect.com:
Whooping Cough in 2014 and Beyond: An Update and Review
Original Research Article Chest, Volume 146, Issue 1, July 2014, Pages 205-214
Joshua D. Hartzell, Jason M. Blaylock
Vaccination
Vaccination for pertussis was introduced in the 1950s and dramatically reduced the incidence of disease, but success was moderated by side effects. Whole-cell pertussis vaccines (ie, diphtheria-tetanus toxoids, wholecell pertussis [DTwP]) were associated with fever (including febrile seizures), local reactions, and hypotonic
episodes. These concerns resulted in their replacement with acellular vaccines (ie, diphtheriatetanus toxoids, acellular pertussis [DTaP]; Tdap; and so forth) in the 1990s. Although acellular vaccines have an improved safety profile, their effectiveness has been called into question. A Cochrane Review demonstrated that the effectiveness of acellular vaccines in preventing typical whooping cough ranges from 59% to 85%. Furthermore, studies demonstrated that having a whole-cell vaccine as any part of the vaccination series improved immunity. A case-control study of children done by Kaiser Permanente Northern California reported that following the fifth dose of DTaP, children were 46% more likely to develop pertussis in each subsequent year. Studies in Minnesota children and from California counties reported similar results of waning immunity with DTaP. These recent reports highlight a clear concern of waning immunity with use of the current acellular vaccines.
There are multiple possible reasons for the decreased efficacy of acellular vaccines, and a full discussion is beyond the scope of this paper. A recent review by Cherry highlights
several of these potential explanations. Others have discussed the importance of antigenic divergence and how it may be affecting memory recall and antibody efficacy. It is clear from the available data that there is a need for newer more immunogenic pertussis vaccines. A recent review suggested that including new virulence factors might be the most appropriate approach. Unfortunately, the development and approval of new vaccine products will take time. In the meantime, the use of the vaccines that we do have could be improved. Vaccination timing is an important component of eliciting immunity. A study of pregnant women reported that passive protection of infants requires vaccination during the third trimester, and it is short-lived. As a result, the current Advisory Committee on Immunization Practices recommendation for pregnant women is that vaccination occur between 27 and 36 weeksâ gestation during each pregnancy to maximize the maternal antibody response and passive antibody transfer to the infant. Future studies should examine the timing of other patient populations (including infants) to determine if different schedules or more frequent boosters may improve outcomes.
Ensuring adequate vaccination coverage remains a challenge. Several studies have demonstrated that there are gaps in coverage (Tdap coverage ranged from 5.9% to
45.5%) and adherence to recommendations, including patients with free access to care and those with adequate insurance coverage. There are multiple barriers to vaccination, including cost, inadequate coordination of adult vaccination activities, lack of provider recommendation for vaccination, health literacy, and concern about adverse events. The problem is amplified worldwide, where an estimated 22.6 million children are not completing the appropriate pertussis vaccination series (three doses in first year of life). Unfortunately, this leaves the most vulnerable patients at risk.
Asta ca sa vezi ca oamenilor de stiinta le place stiinta, si nu sa faca lucrurile sa arate frumos :).
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