DataPokes: May 2013

An Introductory Note

DataPokes is an ongoing monthly forum for the Oregon Immunization Program’s Evaluation & Surveillance team. We will use this as a place to talk about our work and highlight some local, national and international research about immunizations. Even though we can’t promise baskets of kittens or vaccine refrigerators transforming into giant robots, we’ll find some interesting things for you here.

-Steve Robison, Oregon Immunization Program Epidemiologist

Staff Publication: Priming with Whole Cell Pertussis Vaccine

Our own Juventila Liko (et al.) examined whether children who started their early pertussis immunizations with a whole-cell vaccine (DTwP) had less pertussis than those who only had an acellular DTaP vaccine. Using ALERT data for kids born between 1998 and 2000, Liko et al. found that those primed with DTwP had substantially lower pertussis rates, including into their teen years. This benefit to DTwP priming was observed regardless of how many DTaPs a child got or whether they had a tdap booster. Despite these advantages, the whole-cell pertussis vaccine was replaced by acellular DTaP in the United States because of concerns about higher rates of side effects with the whole-cell vaccine. Because of these side effects, returning to the whole-cell vaccine is not a likely option.

(Source: Liko, J., Robison, S., & Cieslak, P. (2013). Priming with whole-cell versus acellular pertussis vaccine, New England Journal of Medicine. 386, 581-582) 

Why We Immunize Teens for HPV

A recent study from Australia has found that the prevalence of genital warts among teens and young adults has drastically been reduced since the introduction of the human papillomavirus (HPV) vaccine in 2007. The reduction was stronger for girls than boys, but both were substantial. In 2007 before the introduction of the HPV vaccine, 11 percent of Australian women under age 21 who visited a sexual health service were diagnosed with genital warts. After the introduction of the HPV vaccine, this prevalence fell to under 1 percent, followed by no reported diagnoses of genital warts in 2011. During the same period, rates for genital warts among adults age 30 and up who did not participate in the Australian HPV program did not change. This study provides good evidence that the HPV vaccine is working.

So what did it take to achieve this result in Australia? In 2010 the Australian HPV vaccine coverage rates for their school-based programs was 83 percent HPV vaccine initiation among 12–13-year-old girls, with a 73 percent series completion rate. In contrast, here in Oregon 45 percent of 12–13-year-old girls have started on HPV vaccine, and only 16 percent have had all three shots, according to ALERT data. We have made progress, but we have a long way to go.

(Source: Ali, H., Donovan, B., Wand, H., et al. (2013). Genital warts in young Australians five years into national human papillomavirus vaccination programme: national surveillance data. British Medical Journal, 346:f2032.)

A Vaccine for Staph? Try and Try Again

One long-running failure in immunology is the inability to develop an effective vaccine against staph bacteria. The evolution of Methicillin-resistant Staphylococcus aureus (MRSA) has led to near panic among some medical authorities, who worry that soon we won’t have any antibiotic options left. In 2012 one more potential staph vaccine failed in human trial. The vaccine was intended for surgery patients two weeks prior to being admitted.

While no adverse effects were seen initially and recipients built resistance to a staph surface protein, the trial was halted early due to adverse surgical outcomes among those who received the vaccine.

This is not the first vaccine failure for staph; historically many have been developed with failure as a uniform result. The ability of staph to acquire and express factors to specifically thwart the human immune system has meant that lab and animal testing cannot reliably guide vaccine development. As staph is a common and harmless colonizer of over a third of the world’s population, disease eradication is not likely anytime soon even if a vaccine for hospital use is found.

(Source: Keller, D. (2012, Oct 22). Staph vaccine linked to multi-organ failure and death. Medscape Medical News. Available at http://www.medscape.com/viewarticle/773037).