Vaccinate the vector?

The new chair of Tulane’s department of tropical medicine, Dr. Nirbhay Kumar, is bringing to Tulane a promising malaria vaccine.
Malaria is a tropical parasitic disease carried by mosquitoes that kills about one million people a year. An effective vaccine against the disease has proven elusive. Malaria has been infecting humans for millions of years and has developed successful ways of evading the human immune response making vaccination strategies less effective.
Kumar will continue working on the vaccine at Tulane. He is also bringing money from his grant to set up a new laboratory and insectary at Tulane in order to perfect the vaccine.
Kumar said, “Hopefully, we will be able to start clinical trials at Tulane in two years.”
The last vaccine trial, just recently published, was conducted in mice and baboons. The vaccine was over 97 percent efficient in the baboons.
Dr. Mark James, professor of immunology and vice chair of tropical medicine, said “The vaccine shows encouraging results.”
Kumar said that the vaccine should be cheap and easy to produce.
“The vaccine will hopefully be able to be provided at little or no cost in developing countries.” He said.
The vaccine that Kumar is currently developing is a transmission-blocking vaccine. The vaccine would not protect the individual vaccinated, but rather lower the chance that that person could transmit the disease. This type of vaccine is commonly referred to as an “altruist vaccine”, referring to the fact that while the vaccine may not protect the individual, it could protect the community.
“People will be willing to get vaccinated if it protects their children and other family members.” Kumar said.
There is another malaria vaccine which is currently in clinical trials, called RTS,S after the protein it immunizes against. It is an infection blocking vaccine and protects the individual immunized, like most traditional vaccines. Potentially the two vaccines could be used in conjunction to thwart infection, and then, if the first vaccine fails, hinder transmission. Kumar, however, would also like his vaccine to be administered alone, and believes it should be effective by itself.
The vaccine is a protein, called Pfs48/45, expressed by the sexual stages of malaria. Escherichia coli (E. coli) bacteria are induced to make the protein, which allows the protein to be made inexpensively and in large quantities. The vaccine is only directed against one species of malaria, Plasmodium falciparum.
The vaccine works by promoting the body’s production of antibodies against the sexual stages of the malaria parasite. The feeding mosquito ingests both parasites and antibodies with the blood meal. The antibodies prevent the parasites from mating in the mosquito and thus can stop transmission of the disease.
James said “The most promising use of the vaccine will probably be in unstable transmission areas. It could be boosted before prime transmission season to curb epidemics.”
The vaccine is currently administered in three separate doses, but Kumar thinks that it is possible that only two will be required for effective immunization.
Tulane’s school of public health and tropical medicine has a strong commitment to global health, and Kumar’s work will hopefully reinforce the school’s reputation.
James said, “It’s good to have someone working on a malaria vaccination at Tulane.”
Kumar also gave high praise to his new university.
He said, “I’m excited to be working at Tulane. It has an excellent history and reputation in tropical medicine.”