Vaccine Epidemiology: Epidemiologic Measures of the Effects of a Vaccine and Vaccination
Conditional parameters like transmission probability and secondary attack rate can provide vaccine effect estimates with less bias and the public health impact of vaccination can be defined by measurements such as “population prevented fraction, population preventable fraciton”.
Abstract
Vaccination is one of the most successful and cost-effective interventions in prevention of diseases. The effect of a vaccine is shown by the percent reduction in the incidence of the relevant disease among vaccinated people compared with those unvaccinated. When the effect of a vaccine is calculated under ideal conditions with randomized controlled studies, vaccine efficacy is obtained and when calculated on the nonideal field conditions with observational studies, vaccine effectiveness is obtained. After a licensed vaccine which its efficacy was identified is introduced into a population, vaccination effectiveness should be monitored as a part of disease surveillance. It should be well known that vaccine efficacy and vaccine effectiveness are not the same concepts. In addition to the direct effect of vaccine on the individual level, the indiret effect, total effect and overall effect of the vaccination programs on the population level should be evaluated. The public health impact of vaccination can also be defined by measurements such as “population prevented fraction, population preventable fraciton”. Conditional parameters like transmission probability and secondary attack rate can provide vaccine effect estimates with less bias. As well as the biological protective effect of a vaccine, exposure or behavior effect, contact rate effect and vaccine effect on infectiousness and OZET Asilama, hastaliklarin onlenmesinde en basarili ve maliyet etkili girisimlerden biridir. Bir asinin etkisi asilananlarda asilanmayanlara gore ilgili hastalik insidansindaki azalma yuzdesi ile gosterilir. Asi etkisi randomize kontrollu calismalar ile ideal kosullar altinda hesaplandiginda asi etkinligi, gozlemsel calismalar ile ideal olmayan saha kosullarinda hesaplandiginda ise asi etkinligi elde edilir. Etkinligi belirlenip lisans alan bir asinin bir toplumda uygulamaya girdikten sonra hastalik surveyansinin bir parcasi olarak etkinligi izlenmelidir. Asi etkinligi ve asi etkililiginin ayni kavramlar olmadigi iyi bilinmelidir. Asinin bireysel duzeyde direkt etkisinin yani sira asi programinin toplum duzeyindeki indirekt etki, toplam etki ve genel etkisi de degerlendirmelidir. Asilamanin halk sagligi etkileri “toplumda korunabilir fraksiyon, toplumda korunan fraksiyon” gibi olcutlerle de belirlenebilir. Bulas olasiligi ve sekonder atak hizi gibi temasa kosullu olcutler ise daha az taraf tutma ile asi etkisi tahmini saglayabilir. Bir asinin biyolojik koruyucu etkisinin yani sira asinin maruziyet etkisi ya da davranissal etkisi, temas hizi etkisi, asinin bulasicilik uzerine etkisi ve asinin birlesik etkisi de bir enfeksiyon etkeninin toplumdaki bulas dinamiklerini anlamada onemli Turk Hijyen ve Deneysel Biyoloji Dergisi 1 Dokuz Eylul Universitesi, Tip Fakultesi, Halk Sagligi Ana Bilim Dali, Epidemiyoloji Bilim Dali, IZMIR Gelis Tarihi / Received : Kabul Tarihi / Accepted : Iletisim / Corresponding Author : Can Huseyin HEKIMOĞLU Dokuz Eylul Universitesi, Tip Fakultesi, Halk Sagligi Ana Bilim Dali, Epidemiyoloji Bilim Dali, IZMIR Tel : +90 542 247 07 18 E-posta / E-mail : drchh@hotmail.com 27.07.2015 23.10.2015 DOI ID : 10.5505/TurkHijyen.2016.90377 Hekimoglu CH. Asi epidemiyolojisi: Asi ve asilamanin etkileri icin epidemiyolojik olcutler. Turk Hij Den Biyol Derg, 2016; 73(1): 55-70. Makale Dili “Turkce”/Article Language “Turkish” Derleme/Review