June 7, 2010

CANADA: Pneumonia vaccine ineffective against repeat infections, claims study

TORONTO, Ontario / National Post / News / June 6, 2010

The PPV vaccine is designed to prevent diseases caused
by the pneumococcus bacteria, which include pneumonia,
sepsis and a type of meningitis — inflammation around the brain.
Ed Kaiser/Edmonton Journal

Tom Blackwell, National Post · Saturday, Jun. 5, 2010

The bacterial pneumonia vaccine given to tens of thousands of Canadians a year appears to do nothing to prevent repeat, often-deadly episodes of the infectious disease, a new study concludes.

Far better immunization strategies are “urgently needed” to curb the number of deaths and illnesses from the pneumococcus bug, say the doctors from Nova Scotia, Ontario and Alberta who spearheaded the research.

As it is now, half of patients hospitalized for pneumonia die or end up in hospital again within five years from another bout of potentially preventable pneumonia or related disease — whether they got the vaccine or not, the study indicated.

The shots were originally tested in the 1970s on young people with strong defences against disease, showing a potent preventive effect. In practice, though, the vaccine is given mostly to elderly people, and likely does not generate a sufficiently robust immune response in them, said Dr. Jennie Johnstone, the lead researcher.

“We need better vaccines and more research into better vaccines: that really is the take-home point,” said Dr. Johnstone, an infectious disease specialist at McMaster University in Hamilton, Ont. “Pneumonia is the number one cause of infectious-disease death in Canada and the sixth-leading cause of death overall. It’s a big problem.”

Ontario alone sees 15,000 hospital admissions a year because of pneumonia, she noted.

Guidelines from the National Advisory Committee on Immunization now call for everyone over 65, certain high-risk children and immune-deficient adults to get the pneumococcal polysaccharide vaccine (PPV). It is designed to prevent diseases caused by the pneumococcus bacteria, which include pneumonia, sepsis and a type of meningitis — inflammation around the brain.

Hospitals and pharmacies alone bought 207,000 units of the serum in 2009, at a wholesale cost of $4.2-million — almost triple the volume in 2005 — according to IMS Health Canada, though many patients would receive it from their family doctor.

The study, just published in the journal Clinical Infectious Diseases, looked at 2,950 patients, most of them senior citizens, admitted to hospital in Edmonton for community-acquired pneumonia. A third had earlier received the vaccine or got it before being discharged.

About half of all the patients ended up back in hospital or died because of pneumococcal infections that theoretically are preventable by the vaccine.

When other factors were filtered out, there was no difference in outcomes between the vaccinated and unvaccinated groups.

Scientific evidence has increasingly raised questions about the product’s efficacy, but the researchers were surprised by the findings. “I thought we would see a difference,” Dr. Johnstone said.

The physician said there is still some value, however, in administering PPV, as it is safe and other studies indicate it can, at least, make pneumonia cases less severe, if not prevent them.

Meanwhile, there is one promising alternative vaccine in human trials now in the Netherlands, but it would protect against a relatively small number of strains of the bacteria. Little attention has been given to a new pneumococcus shot until recently because “people thought: ‘we have a vaccine,’ ” said Dr. Johnstone.

Dr. Andrew Potter, CEO of the University of Saskatchewan’s Vaccine and Infectious Disease Organzation, said the results did not surprise him, as vaccines generally do not work as well on seniors as young people.

He believes, in fact, the whole approach to immunization has to change from the current tendency to vaccinate children extensively, then do nothing until decades later when people enter old age. Elderly patients would do better if they had received vaccines while younger adults, he said.

“You can actually redirect the immune response earlier in life to do what you want it to do later on,” said Dr. Potter. “I just don’t buy the idea that we need a 50-year gap between that first set of immunizations and starting to do it again.”

Tom Blackwell
E-Mail: tblackwell@nationalpost.com

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