Vaccination and E. coli O157:H7

Yesterday, the NY Times had an article about using vaccination to eliminate or greatly reduce E. coli O157:H7 infections. Strategies differ: some would vaccinate the cows, while others would vaccinate people. The new threat due to E. coli O157:H7 isn't from contaminated meat, but from contaminated vegetables, such as the spinach outbreak. Unfortunately, I don't think vaccination is going to work.

We'll ignore the notion that if we were to institute a mass vaccination campaign of either cattle or people, we might want to target something that kills more than 61 people per year, and, in fact, causes a fraction of the E. coli-related deaths in the U.S. Influenza comes to mind. Just sayin'.

But let's pretend that spending hundreds of millions, if not billions, of dollars to vaccinate against a disease that kills very few people is a good idea even though, as is pointed out in the article:

Michael T. Osterholm, director of the Center for Infectious Disease Research and Policy at the University of Minnesota, said he was skeptical about all the approaches. "What really is a concern to me about this issue is we always have a tendency to want high-tech responses to what in many cases are common-sense low-tech solutions," Dr. Osterholm said.

He is a consultant to Fresh Express, the leading seller of bagged salads, and is head of a committee that will disburse $2 million from the company for research on how the produce industry should handle E. coli. He said stringent safety procedures had kept that company from having any contamination incidents.

In any case, even if a high-tech solution was desired, there does not seem to be a vaccine for spinach as there is for cattle.

OK, about that vaccination idea:

1) Most food-related deaths due to E. coli are not due to O157:H7. The vaccine won't protect against them.

2) Bacteria evolve rapidly, and to acquire through gene transfer, new antigen types can happen pretty quickly. O157:H7 might evolve new antigen types (and thus not be 'O157:H7'), but still be capable of causing disease.

3) One of the things that makes O157:H7 so nasty is what is known as shiga toxin. There are many different serotypes of shiga toxin producing E. coli that would not be covered by the vaccine. There's no reason to think that these other E. coli won't increase in frequency. In fact, where the Streptococcus pneumoniae vaccine is widely used, we see an increase of 'non-covered' bacterial serotypes that are associated with disease.

This doesn't mean that all bacterial vaccines are a bad idea. The S. pneumoniae vaccine prevents thousands of deaths (and should be used more widely). Ditto the Haemophilus influenza vaccine (often referred to as "H-flu"). There's even an idea afloat to vaccinate against some of the common commensal E. coli that can also cause urinary tract infections. With all of these vaccines, however, constant surveillance is required to adjust the vaccine to deal with new serotypes.

You know, if evolution didn't happen, this whole infectious disease thing would be a lot easier....