There are many recent studies and articles showing problems with the efficacy of the pertussis vaccine. So many, in fact, that vaccine manufacturers should be queried and held to a higher burden of proof as to the true performance of their products.
Note: If you or someone you care about may have pertussis, see our post on The Vitamin C Treatment of Whooping Cough by Suzanne Humphries, MD for some guidance on what you might do to help them.
The following information comes from recent studies with regards to the poor performance of the Pertussis vaccine:
California:
“In early 2010, a spike in cases appeared at Kaiser Permanente in San Rafael, and it was soon determined to be an outbreak of whooping cough — the largest seen in California in more than 50 years. Witt had expected to see the illnesses center around unvaccinated kids, knowing they are more vulnerable to the disease. “We started dissecting the data. What was very surprising was the majority of cases were in fully vaccinated children. That’s what started catching our attention,” said Witt. To figure out just how well the vaccine was working, Witt and his colleagues collected information on every patient who had tested positive for pertussis between March and October, 2010. Of the 132 patients under age 18, 81 percent were up to date on recommended whooping cough shots and eight percent had never been vaccinated. The other 11 percent had received at least one shot, but not the complete series. The rate of cases for each age, two through 18 years old, peaked among kids in their pre-teens. Among fully immunized kids, there were about 36 cases for every 10,000 children two to seven years old, compared to 245 out of every 10,000 kids aged eight to 12.” and “…the vaccine is effective about half of the time for all kids, and just 24 percent of the time in the eight to 12 year old age group. “It’s likely if we move doses around we’d shift the burden of disease, but not necessarily reduce it,” A spokesperson for GSK, one of the pertussis vaccine makers, wrote in an email to Reuters Health that studies conducted by the company have shown the vaccine is about 78 percent effective in warding off disease up until the age of six years. GSK has never studied the duration of the vaccine’s protection after the shot given to four- to six-year-olds, the spokesperson said.”
http://www.reuters.com/article/2012/04/03/us-whoopingcough-idUSBRE8320TM20120403
Israel
“Pertussis is considered an endemic disease, characterized by an epidemic every 2–5 years. This rate of exacerbations has not changed, even after the introduction of mass vaccination – a fact that indicates the efficacy of the vaccine in preventing the disease but not the transmission of the causative agent (B. pertussis) within the population.” http://www.ima.org.il/imaj/ar06may-2.pdf
Netherlands
“An important issue is whether vaccination has selected for the ptxP3 strains. Several lines of evidence support this contention.” “Based on mathematical modeling, vaccines designed to reduce pathogen growth rate and/or toxicity may result in the evolution of pathogens with higher levels of virulence” The authors “propose that waning immunity and pathogen adaptation have contributed to the resurgence of pertussis, although other factors such as increased awareness and improved diagnostics have also played a role.” http://wwwnc.cdc.gov/eid/article/15/8/08-1511_article.htm
Finland
“Pertussis is an infectious disease of the respiratory tract caused by Bordetella pertussis. Despite the introduction of mass vaccination against pertussis in Finland in 1952, pertussis has remained an endemic disease with regular epidemics.” and “During the last decade, the number of pertussis cases has increased in countries with high vaccination coverage rates including Finland.” http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1233997/
“Reemergence of pertussis has been observed in many countries with high vaccination coverage. In the United States, reported cases of pertussis in adolescents and adults have increased since the 1980s, despite increasingly high rates of vaccination in infants and children. At the same time, clinical B. pertussis isolates have become antigenically divergent from vaccine strains. This observation has raised the question of whether vaccination has caused selection for the variant strains, and whether the reemergence of pertussis in vaccinated populations is due to vaccination not protecting against these antigenic variants as effectively as it protects against vaccine type strains. On the other hand, vaccine-induced immunity wanes over time, and pertussis is not only a childhood disease but also a frequent cause of prolonged illness in adults and adolescents today.” http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3294326/
Finally, here is a study published in the Journal of the American Medical Association showing that despite vaccine coverage of 98% both pertussis and para-pertussis outbreaks appeared in Finland. Their conclusion was that, “Bordetella infections are common in an immunized population, and B parapertussis infections apparently are more prevalent than previously documented.” http://jama.ama-assn.org/content/280/7/635.full
By the way, West Virginia, which allows medical exemptions only, has had a pertussis outbreak this year. http://www.dhhr.wv.gov/oeps/disease/Documents/WV_HAN_59.pdf