Doctors say a vaccine is on the horizon for tularemia, a fatal disease caused by the pathogen Francisella tularensis, an organism considered a potential biological warfare agent. Until recently medicine knew very little about this bacterium.  But, according to the August issue of the Journal of Medical Microbiology, research on the bacterium is now making fast progress.

Infection with F. tularensis can result in a variety of symptoms, depending on the route of infection. For example, infection via an insect bite can lead to a swollen ulcer or fever, chills, malaise, headaches and a sore throat. When infection occurs by eating contaminated food, symptoms can range from mild diarrhea to an acute fatal disease. If inhaled, F. tularensis infections can have a 30 percent mortality rate if left untreated.

“Very few bacteria are needed to cause serious disease,” said Dr. Petra Oyston. “Because of this and the fact that tularemia can be contracted by inhalation, Francisella tularensis has been designated a potential biological weapon. Since the events of September 2001 and the subsequent anthrax attacks on the USA, concern about the potential misuse of dangerous pathogens including F. tularensis has increased.”

Tularemia resides in rodents and animals like rabbits and hares. Outbreaks in humans often happen at the same time as outbreaks in these creatures. The disease is probably transmitted by insects like mosquitoes, doctors speculate. People can also become infected by contact with contaminated food or water. Farmers, hunters, walkers, and forest workers are most at risk of contracting tularemia.

Presently, there is no vaccine against tularemia. Since there are few natural cases of tularemia, money was not spent by researchers on the development of a vaccine. But, some nations have developed F. tularensis as a biological weapon, including the reported production of antibiotic-resistant strains, so research into its pathogenesis has become a biodefense issue.

“Progress is being made,” said Dr. Oyston. “Since the genome of F. tularensis was sequenced, researchers have taken great strides in understanding the molecular basis for its pathogenesis. This is essential information for developing a vaccine and getting it licensed.”

– by Gene J. Koprowski, Editorial Director

Biological warfare still a threat in the years after 9-11.

Posted: July 28th, 2008 under Anti-Bacterial Resources, Vaccinations.
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Vaccine development is taking an encouraging turn by moving towards a process that involves far less scientific uncertainty.

Immune Design, a Seattle-based biotech start-up, recently raised $18 million to further research on immunological adjuvants that specifically seek out dendritic cells, an integral part of the immune system.

Dendritic cells are present in tissues having contact with the external environment, notably the skin, nose, lungs, stomach and intestines. They are also present, in an embryonic state, within the blood. When a perceived threat is encountered, dendritic cells capture the invading matter and carry it into the lymph tissues, where they present it to T- and B-cells to initiate the appropriate immune response. Vaccine developers have never before focused on this part of the immune system.

Traditional vaccines don’t specifically target the cells that are necessary for an effective response, says Dr. Steven Reed, founder of Seattle’s Infectious Disease Research Institute and CEO of Immune Design. “We want to make it an exact science,” he adds.

Immune Design scientists, like Dr. David Baltimore, eminent immunologist and Nobel Laureate; Dr. Larry Corey, Chief of Infectious Diseases at the Fred Hutchison Cancer Research Center; Dr. Lili Yang of Cal Tech; and Dr. Pin Wang of the University of Southern California, seek to formulate lipids, proteins, and other molecular adjuvants that stimulate response in dendritic cells, thus jump-starting an immune response or bolstering immunity after it has already been compromised. This has tremendous potential for the treatment of diseases involving weak or malfunctioning immune systems, scientists say.

“For many diseases, such as HIV and other chronic viral diseases such as hepatitis and herpes and influenza, the vaccines don’t exist or are not very effective,” says Reed. Immune Design hopes to have its first product in clinical trials within a year.

Advances towards a more exact vaccine technology are part of medicine’s infectious disease-fighting history.

Late Imperial Chinese doctors developed the process of ‘variolation’–distinctly different from vaccination as we know it. Doctors and healthy subjects inhaled a fine powder made from the scabs of other patients’ active smallpox sores. Another method was to scratch the skin of a healthy patient and anoint it with the pus from a victim’s active sore. The effect was controlled exposure of a healthy body to a less virulent form of the infection. The process proved effective, medical historians say.

Johns Hopkins History of Chinese Medicine Professor, Dr. Marta Hanson, notes that ancient medicine in several cultures knew about primitive vaccination techniques.  “They [Chinese physicians] share the honors with Indian Ayurvedic medicine, which has even earlier evidence of variolation practices.”

Yet, neither culture genuinely recognized the concept of protective resistance. Chinese medicine is focused on improving the flow of energy through the body, for example, rather than focused on microbes, as is modern, western medicine. 

 “They generally thought they were releasing toxins from when a person was a fetus,” explains Hanson. “There was no understanding of immunity in that period, as we understand it today.”

Infection Protection editors wonder whether it is possible to entirely remove trial and error from vaccine development.

 Hanson, whose specialty is history of epidemics and disease in China, remains cautiously optimistic.

“I think trial and error can be reduced through this kind of research but not entirely removed,” says Hanson. “This projected discovery sounds promising.”
 

– by Savannah Schroll Guz, MA, Pittsburgh Correspondent
 

Further Reading:

John Carroll, “Emerging Drug Developer: Immune Design,” FierceBiotech, June 30, 2008, http://www.fiercebiotech.com/special-reports/emerging-drug-developer-immune-design (accessed June 30, 2008).

Megan Gressor. “Milestones in Medicine,” Sydney Morning Herald, February 13, 2005,
http://www.smh.com.au/articles/2005/02/17/1108500190027.html (accessed June 29, 2008).

National Institute of Allergy and Infectious Diseases, “Closing In: The Long Road to a TB Vaccine,” Prevention: Vaccine Development, http://www3.niaid.nih.gov/topics/tuberculosis/Research/prevention/prevention_road.htm (accessed June 28, 2008).

Posted: July 7th, 2008 under Developing Diseases, Impaired Immunity, Vaccinations.
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An epidemic of pertussis among babies who were infected by a health care worker has increased calls to get adolescents and adults vaccinated against the infection, according to a report in a leading medical journal.

“We think it’s very important that people do everything to prevent pertussis in infants, and this means immunizing teens, adults, parents of infants, and people who are taking care of infants. It means immunizing health care workers,” said Don Murphey, M.D., lead author of the paper outlining the incident published in the Morbidity and Mortality Weekly Report. He is also the medical director of occupational health at Cook Children’s Medical Center in Ft. Worth, Texas. The infants were infected at another hospital in his community.

The outbreak occurred a year before the Food and Drug Administration’s 2005 approval of Tdap — the vaccine that includes the pertussis immunization — for adults and adolescents. The American Medical Association encourages health care workers to be immunized for their own protection and to reduce transmission to others. But most experts suspect that many health care professionals remain unimmunized.

“Patients should have the right and every expectation that they’re not going to get diseases that they didn’t have when they went into the exam room or hospital,” said Greg Poland, M.D., professor of medicine and director of the vaccine research group at Mayo Clinic in Rochester, Minn.

No information has been collected on how many health care workers have received the Tdap vaccine, although numbers pertaining to the general adult population are not encouraging.

According to statistics released earlier this year by the Centers for Disease Control and Prevention’s National Immunization Survey, 2.1 percent of 18-to 64-year-olds had received it. Also, a study published in the November 2007 issue of the journal Infection Control and Hospital Epidemiology found that 87 percent of health care workers were not planning to receive it.

Experts are concerned because health care workers are more likely to get pertussis in the course of their work, and are more likely to transmit it to vulnerable patients.

– by Gene J. Koprowski, MA, Editorial Director

Posted: July 1st, 2008 under Developing Diseases, Impaired Immunity, Vaccinations.
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Britain is in the midst of a measles epidemic, the country’s public health watchdog says. The Health Protection Agency (HPA) warns that the total number of unvaccinated children was now large enough to sustain the “continuous spread” of the potentially lethal virus throughout the U.K.  HPA blamed a failure by parents to give their children the measles, mumps and rubella (MMR) vaccine.

This has resulted in vaccine rates falling below the level necessary to prevent the disease from becoming established in the general population, doctors say.

The report said: “Due to almost 10 years of sub-optimal MMR vaccination coverage across the U.K., the number of children susceptible to measles is now sufficient to support the continuous spread of measles.

Figures released this week show cases of measles in London reached a new peak last month, exceeding last year’s monthly record set in August 2007, and are continuing to rise.

A total of 95 cases of measles confirmed in London and 35 in the rest of England and Wales bringing the total for the year to 461.

Recently, a 17-year-old patient from West Yorkshire died from the disease. In another case, a physician working in a hospital cancer ward contracted measles.

Fifty years ago, a measles epidemic killed 500 children a year in the U.K. Last month’s death was only the second in more than a decade.

The HPA, which published the latest figures in its weekly report, said the rise in measles cases in London was linked to an outbreak at a secondary school which had spread to neighboring schools and nurseries in the capital.

– by Gene J. Koprowski, Editorial Director

Children are dying of measles once again.

Posted: June 24th, 2008 under Diseases, Measles, Mumps, Rubella, Vaccinations.
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Six children in the northwest suburbs have contracted measles, the Cook County Department of Public Health said. The government agency is urging parents to have children vaccinated to prevent a recurrence of this unusual outbreak of the disease.

Measles presents with a number of common symptoms, including a rash, high fever, cough, runny nose and red, watery eyes. Additional complications from measles infection can be severe, including ear infections, diarrhea or even pneumonia in 6 to 20 percent of cases. A patient may also suffer encephalitis, an inflammation of the brain, or death.

“When parents make the decision to withhold childhood immunizations, it can have devastating effects on the health of their children and the lives of others,” Department of Public Health chief operating officer Stephen Martin said. “Vaccinations are the safest and most effective means to prevent serious illness.”

Measles may be prevented with routine vaccinations, which give lifelong immunity, and by proper infection control

“Measles is a very serious illness and we have seen a surge in cases in unvaccinated persons in our region this year,” Martin said.

– by Gene J. Koprowski, Editorial Director

Measles causes many symptoms, including rash, high fever, cough, and runny nose.

Posted: June 24th, 2008 under Diseases, Measles, Pneumonia, Vaccinations.
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An infection control expert in New Zealand is praising the introduction of a vaccine against pneumococcal disease that will replace the meningococcal B vaccine.

New Zealand Health Minister David Cunliffe says the meningococcal B vaccine campaign would end this year because it was no longer needed.

Henceforth, the government will fund Prevenar vaccinations to immunise children against pneumococcal disease.

Two years ago, 151 children under the age of five contracted a severe strain of pneumococcal disease that can cause pneumonia, blood poisoning, and brain infections, experts tell Infection Protection.

Physician Tim Blackmore says the physical symptoms of meningococcal disease are more dramatic, but pneumococcal disease has become much more prevalent.

Dr. Blackmore says the meningitis of pneumococcal disease is more likely to have long-lasting effects on children, including “permanent hearing or sight loss and learning disabilities.”

The doctor says Australia and Britain already vaccinate children with Prevenar, and the vaccine was previously licensed but not funded in New Zealand.

– the Editors

Posted: April 15th, 2008 under Diseases, Vaccinations.
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Copenhagen-based Bavarian Nordic said this week its Imvamune vaccine has a “therapeutic effect” on smallpox even in animals who are already infected. The company first published news of the discovery in a paper in the Journal of Clinical Investigation.

A single dose of Imvamune given to mice up to three days after infection with the Ectromelia virus — a natural poxvirus that closely models human smallpox — protected the animals from the lethal infection. “It opens up new and exciting smallpox preparedness possibilities,” Bavarian Chief Executive Anders Hedegaard said. “We can offer a safer vaccine and a solid protection both before and after exposure. No other smallpox vaccine has shown to offer these important features.”

Last year, the company won a contract from the U.S. government for the development and delivery of 20 million doses of Imvamune for a stockpile in case of biological attack from terrorists. The first deliveries start next year.

– by Gene J. Koprowski, Editorial Director

 

New vaccine proves effecive against smallpox in lab mice.

Posted: April 11th, 2008 under Diseases, Vaccinations.
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Reuters is reporting from Toronto — Canada suspended use of three batches of a mumps vaccine this week after five people fell ill in the middle of a massive vaccination campaign. The government agency Health Canada advised against the use of the three lots of measles, mumps and rubella vaccine sold by MerckFrosst Canada, due to suspected cases of anaphylaxis, a potentially life-threatening allergic reaction characterized by swelling and difficulty breathing. “Because all of our vaccine producers now are all global, then we also reach out globally to determine whether or not there are any other adverse events or clusters of adverse events that people are seeing elsewhere related to this product, or related to any of these lots that may be gone elsewhere,” said Dr. Arlene King, a director with the Public Health Agency of Canada.

See,

http://ca.today.reuters.com/news/newsArticle.aspx?type=domesticNews&storyID=2007-12-12T231854Z_01_N12627558_RTRIDST_0_CANADA-MUMPS-COL.XML&archived=False

We hear that this is a collaborative investigation by Health Canada, the Public Health Agency of Canada and Health Alberta with distributor MerckFrosst Canada. Scientists are also soliciting reports of adverse events from other countries that use the measles, mumps and rubella vaccine, MMR-II.  Merck & Co Inc markets the vaccine in the European Union, Australia, Hong Kong, China, Argentina, Russia, the U.S., and overseas. Investigators expect to take several weeks before they complete an analysis of both the adverse events and the vaccine itself. If the batch is in fact defective, those immunized with it may have to take other infection protection measures.  – The Editors

Posted: December 13th, 2007 under Infection Protection, News, Vaccinations.
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