Pertussis vaccine waning effectiveness – the facts

pertussis vaccine waning effectiveness

The issues with the pertussis vaccine waning effectiveness has been circulating for several years. There have been a number of well-designed studies that have provided evidence of the issues with the pertussis component of the DTaP or Tdap vaccine (which also provides immunization against tetanus and diphtheria, both dangerous diseases).

According to current research, individuals who have been vaccinated against whooping cough (Bordetella pertussis), with either the DTaP (version for usually for children) or Tdap vaccine, lose protection against whooping cough in some time period after being vaccinated.

A new article, published in Pediatrics, written by Nicola P Klein et al.,  examined children who received the Tdap vaccine in the Kaiser Permanente Northern California (KPNC) health care plan, a vertically integrated managed care system which closely tracks patients after vaccination. Their data provide important information about the strategies for the vaccine going forward.

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Comparing effectiveness of two types of pertussis vaccines

whooping-cough-cocoonOver the past year or so, there have been several outbreaks of whooping cough (Bordetella pertussis), including one that reached epidemic levels in Washington state, which has been considered one of the worst pertussis outbreaks in the USA during the past several decades. The disease lead to 18 infant deaths from whooping cough during 2012.

The original DTP vaccine (diphtheria, tetanus and pertussis) became available in the USA in 1948 and was critical to dropping the number of cases of whooping cough from 260,000  in 1934 to less than a few thousand per year in the 1990’s. The original vaccine contained what was called “whole-cell” pertussis, which includes all of the antigens of the pertussis bacterium, partially because it wasn’t understood (and to some extent still not fully understood) which antigens on the bacteria actually induce the proper immune response to have the body destroy a pertussis infection.  Continue reading “Comparing effectiveness of two types of pertussis vaccines”

Whooping cough vaccine–facts about waning immunity

A new article published this week in the Journal of the American Medical Association (JAMA) by Misegades et al. analyzed a recent whooping cough (Bordetella pertussis) outbreak in California children. Misegades determined that those who had not been vaccinated against the disease were nine times more likely to get pertussis than those who had received the entire five-shot series. However, among children who were fully vaccinated, the longer it had been since their final dose of the DTaP vaccine (which protects against diphtheria, tetanus and pertussis), the higher the risk of contracting whooping cough. This is in line with the decrease in effectiveness of the vaccine that has been discussed here and elsewhere. Continue reading “Whooping cough vaccine–facts about waning immunity”

Whooping cough–effectiveness of pertussis vaccines

This year has been a bad one for whooping cough (Bordetella pertussis) throughout the world. There have been large outbreaks of pertussis in the United States, England and Australia in 2012. There have been some hypotheses as to why it has been happening. For example, there is some speculation that a subtype (or genotype) of pertussis was responsible for the Australian outbreak, but the evidence is complicated and equivocal. I think there is some evidence that the epidemic in Washington state results from the much lower vaccination rates in the area as a result of the anti-vaccination lunacy. 

But the story may be much more complicated, and may need a more open discussion amongst those responsible for protecting us from these infectious diseases. These pertussis outbreaks may be a result of the reduced performance of the pertussis vaccine currently being used. The problem with an open discussion regarding the current vaccine is that the vaccine denialists will make an absolute claim that the pertussis vaccine does not work (of course, a complete fabrication, typical of the anti-vaxxers), instead of the more accurate position that the pertussis vaccine might not have the high level of effectiveness that was originally thought. Ironically, the current vaccine, the acellular pertussis version, replaced the older and more effective whole pertussis vaccine because critics believed the older version had too many side effects. Continue reading “Whooping cough–effectiveness of pertussis vaccines”