Vaccine-resistant whooping cough found in Philadelphia

When we talk about the resurgence of childhood illnesses, we tend to focus on vaccine-resistant people as the primary cause. And it's true that a large population of un-vaccinated kids can give a disease like whooping cough a foothold in a community, and allow it to spread to kids who haven't been vaccinated yet or who can't be vaccinated for various medical reasons. But there's another facet to this story, as well. Some of the strains of bacteria that cause whooping cough are also resistant to the vaccine. Those strains have been found in Japan, France, and Finland. Last week, The New England Journal of Medicine reported on 12 cases of vaccine-resistant whooping cough in Philadelphia.


  1. Is there any word yet on the expected difficulty of reformulating to counter the new strain?

    With something like the flu, say, it moves sufficiently fast that they’ve gotten reformulating down to a routine, with the major challenge being guessing the hit strain of the year far enough in advance to start the process.

    With other pathogens, years of research have failed to produce a vaccine that works against any flavor of the bug.

    1. Bacteria are good targets for for vaccines.  Some viruses mutate very fast, parasites often have elaborate tricks to avoid the immune system, but bacteria are usually good targets for vaccine. 

    1. Jen, yes anti-vaccine people are a problem when it comes to getting adequate herd immunity in a population. 

      However, the problems we are seeing with B. pertussis are far more complicated than just getting everyone vaccinated.  They are forcing researchers to rethink how they are designing, implementing and monitoring vaccine regimes.

    2. Except it’s the over-vaccinating that causes mutant strains to develop more quickly. Nature will always find a way.

  2. Vaccination for B. pertussis has moved to an acellular vaccine that includes 2-3 major proteins that are immunogenic (detectable by the immune system) and specific to virulent strains of the bacteria.  The change-over occurred because there are fewer side-effects associated with an acellular vaccine versus a whole-cell vaccine.  If you have journal access, there was a good research article on the state of the B. pertussis vaccine in the Journal Vaccine ( ). 

    The problem is children don’t get the same kind of immunity that they would with a whole-cell vaccine as their immune system is only building a response to specific proteins that we have identified as being associated with the virulent bacterium.

    What the NEJM letter is indicating is that the specific proteins we target with modern acellular vaccines (namely pertactin) are undergoing selective pressure to either become removed from the bacterium or mutated. This means that the immunity we receive from the vaccine does not necessarily allow our immune systems to detect/target the bacterium.

    Research groups are looking at and have added additional proteins specific to B. pertussis to the current vaccines but whenever we are targeting something specific we are always going to run the risk that the organism we are targeting will mutate to become resistant. Life has a funny way of trying to outsmart us as we solve these problems with novel solutions.

    1. Thank you for a clear explanation.
      I wonder if its just part of the “normal” mutations that happen in nature, but because we’ve changed the habitat the mutants are surviving and being given a leg up.

  3. Bacteria aren’t “resistant to a vaccine” because  the vaccine doesn’t kill the bacteria.  The vaccine resembles the bacteria, and the body does the killing after it has been primed by the vaccine.  

    Presumably, the bacteria are still immunogenic and capable of creating an immune response and being recognized by the immune system.

    However, the vaccine is now outdated because it is not a good match to these new strains. The vaccine is not creating an immune response against these new strains.

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