(Bloomberg) — What if a drugmaker spent billions of dollars to create a vaccine — only to find out humans developed natural resistance to the disease before its product is ready?
That is part of the scenario GlaxoSmithKline Plc and other pharmaceutical giants are weighing in their cautious approach to developing a Zika vaccine.
Large portions of the populations in Zika-affected areas could develop immunity to the virus over the next five to 10 years, slowing its circulation into virgin areas, said Moncef Slaoui, chairman of London-based Glaxo’s vaccines division. That would make it harder to determine the market for a vaccine, which could be just stockpiled for outbreaks rather than used widely during national immunization campaigns.
Although fear of the virus remains high in the United States and its territories — where almost 300 pregnant women have shown signs of possible infection, according to the Centers for Disease Control and Prevention (CDC) — lawmakers are pushing back on funding to fight it. Glaxo, Merck & Co. and Johnson & Johnson are all moving slowly, in contrast with their reaction to Ebola two years ago, when the drugmakers doubled down on developing a vaccine before their efforts stalled as the outbreak in West Africa waned.
See also: J&J Ebola vaccine has promise as wider test awaits next outbreak
“The notion is not that there is no need for a vaccine” for Zika, Slaoui said. “What’s not predictable is how to use this vaccine.”
The World Health Organization declared Zika a public health emergency in February and began an emergency research and development plan for tests, vaccines and drugs. While Ebola is a deadly virus that killed more than 10,000 people in the latest outbreak, Zika doesn’t cause serious illness in most infected people. Zika is a major threat mainly to pregnant women, as it can trigger severe birth defects, and is also linked to an increase in cases of a rare neurological disorder.
“While Zika has a high potential impact on women of reproductive age, its limited effect on general health could easily see funding wane, particularly if Ebola saw resurgence or another pandemic threatened,” market analysis firm BMI Research said in a May 20 report.
Clinical development will probably take more than three years, Sanofi has said. It took the Paris-based company 20 years to bring its dengue vaccine to market, and the infrastructure it built up during that time makes it easier to begin work on a Zika inoculation.
“We have scientists, clinicians, toxicologists, epidemiologists that understand this family of viruses,” said Nicholas Jackson, who heads the Zika vaccine project for Sanofi. “This gives us a great opportunity to move quickly, and quick is needed here.”
The U.S. government, meanwhile, is working on a potential vaccine that will enter human trials in September, said Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases. If it passes safety tests, it will enter effectiveness trials in the first half of 2017. At that point, the timeline will depend on the size of the outbreak the world is facing.
“If there’s still a major outbreak, they could have an emergency use of that vaccine and make it available sometime in 2018,’’ Fauci said. “Or –-and that’s a big or -– if in fact, we don’t have a lot of infections, it may take three or more years to prove’’ that the vaccine is effective and to win regulatory approval.
While Glaxo, J&J and Merck are among the world’s pre-eminent developers and manufacturers of inoculations, they are absent from the list of companies that have shared details with the WHO on vaccine candidates. But all three have emphasized that they are making some early efforts.