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Just 12 hours after he got an experimental Ebola vaccine, and just two days after he stuck himself with a needle while caring for Ebola patients in September, Dr. Lewis Rubinson started getting sick.

By then, Rubinson was aboard a jet, being evacuated from Sierra Leone to the United States. He wasn’t sure if he was infected with Ebola or if the vaccine was causing a reaction. He was en route to strict isolation at the National Institutes of Health outside Washington D.C.

Months later, it’s fairly clear the vaccine caused the reaction. He has no trace of Ebola infection. What’s not entirely clear is whether the vaccine stopped the virus from taking hold, or whether he was never infected in the first place.

“My gut leads me to believe he was never exposed. You can never prove it,” Thomas Geisbert, an Ebola vaccine expert at the University of Texas Medical Branch, Galveston, told NBC News.

“You need a vaccine that works quick."

Rubinson wrote about his experience in an essay published in the American Journal of Tropical medicine and Hygiene.

“While providing clinical care in the confirmed ward of the Ebola Treatment Unit at the Kenema Government Hospital in Kenema, Sierra Leone, I accidentally stuck an 18-gauge hollow-bore needle deep into my left thumb,” he writes.

“I could immediately feel some blood oozing under my gloves, and I squeezed the area of penetration to try to promote additional bleeding. I rinsed the outside of my gloves with the only available option—0.5 percent bleach.”

It’s a classic needle-stick accident. Doctors, nurses and technicians catch a range of horrible diseases this way, from HIV to Ebola. If a needle has even a tiny bit of infected blood on it, it mainstreams a virus into the bloodstream.

Rubinson had two choices: an experimental drug made by Canadian company Tekmira, or an experimental Ebola vaccine that had not, at that time, ever been tested in humans. Rubinson chose the vaccine.

He was put aboard a specially equipped jet for the long flight to Maryland and vaccinated.

“The patient developed malaise, nausea and fever 12 hours after the vaccination while on the transport jet,” Dr. Mark Mulligan of Emory University and colleagues wrote in a study published in the Journal of the American Medical Association Thursday.

They could have been symptoms of Ebola, or from the vaccine, which is made using a "live" virus called vesicular stomatitis virus (VSV) genetically engineered to carry a small, non-infectious piece of Ebola virus. By design, the vaccine causes a mild infection that activates the immune system and helps it recognize Ebola.

“On day two, the fever declined; however, severe symptoms continued along with mild nausea and arthralgia (joint pain),” Mulligan’s team wrote. “On days three through five, the patient experienced resolution of symptoms and laboratory abnormalities. By day seven, he was completely asymptomatic.”

It's not even clear if all the symptoms were caused by the vaccine. Rubinson could have caught a number of other bugs in Sierra Leone, also.

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Since then, the vaccine has been tested in dozens of people and it’s being rolled out in Sierra Leone, Liberia and Guinea in several different trials to try and find the best way to help stop the epidemic of Ebola that’s infected close to 24,000 people and killed 10,000.

Geisbert, who helped test the vaccine, says one person’s case doesn’t offer a lot of information about how the vaccine will work.

“It shows that there was a robust immune response against the vaccine in one person,” said Geisbert, who wrote a commentary in JAMA about the study.

More importantly, the incident shows just how important it is to develop vaccines against diseases such as Ebola. Researchers had been working on one for years, but development had not gone far because of a lack of funding.

Geisbert hopes the Ebola epidemic will spur work on this and other vaccines, as well as drugs. He hopes Congress — which approves funding for such research — doesn’t lose interest. And he is glad drug giants Merck and GlaxoSmithKline are taking the vaccines to the final stages.

“It’s good to see big companies involved finally,” he said. “Hopefully, there’s funds there to push this across the finish line.”

Whether the vaccine protected Rubinson doesn’t matter. It was having something on hand that counted. Ebola’s infected 839 health care workers and killed 491 of them, according to the World Health Organization. “You need a vaccine that works quick,” Geisbert said. “For God’s sake, vaccinate the first responder and health care workers, the ambulance drivers.”

Giving a vaccine against an infection after someone’s exposed is called post-exposure prophylaxis or PEP. That’s what people get when they undergo rabies shots after an infected animal bites. Some vaccines can prevent infection even after someone has the virus in their body.

Rubinson said it was helpful to think it was the vaccine giving him fever and chills.

“I was fairly sure that my symptoms were consistent with the PEP intervention; however, my anxiety started to increase as I lay in bed freezing under a multitude of blankets,” he wrote.

“After caring for hundreds of persons with Ebola virus disease, I knew that my symptoms were consistent with early Ebola virus disease. I reassured myself that my condition was more likely to be explained by the PEP.”

Geisbert says the strong reaction showed the vaccine was working well.

“There is this debate all the time about live vaccines versus killed vaccines,” he said. “Live vaccines protect better and they last longer. But the trade-off is that because it replicates or grows more, people tend to have adverse events with a live vaccine.”

For an illness that’s not especially common or life-threatening — think many childhood vaccines — a killed virus is an obvious choice. But for Ebola, with a death rate approaching 70 percent, Geisbert argues a live vaccine is far better.

“If I were going to the hot zone in Sierra Leone, I’d choose the VSV vaccine, hands-down.”

A trial of VSV vaccine is just getting under way in Guinea. The Centers for Disease Control and Prevention is preparing a trial in Sierra Leone and trials are starting in Liberia. Trials of drugs such as ZMapp and brincidofivir are also starting.

“To me, the best way to stop this and contain it are the vaccines,” Geisbert said.

Rubinson said he is sad about two things — that he got better treatment than his Sierra Leonean colleagues, and that the U.S. response to anyone coming back with Ebola was so overwrought.

“It was also very hard for me to reconcile that I was not ill and likely never to be ill, but I was to be assisted with tremendous resources to get me back home,” he wrote.

“If I were going to the hot zone in Sierra Leone, I’d choose the VSV vaccine, hands-down.”

“At the same time, many West Africans were actually ill or dying with Ebola, and most were unable to get anything beyond very basic healthcare. This truth would continue to plague me throughout my experience.”

Rubinson opted to keep his identity a secret while he was treated at NIH.

“En route to the United States was the first time that I had insight into the fear and politics of Ebola virus disease that would engulf the United States during the next weeks,” he wrote.

“While refueling in the Azores, the U.S. Air Force leadership on site made it very clear that we were not to open the door to the Gulfstream. I was approximately 50 hours from exposure and asymptomatic: not a risk to anyone, but someone who was feared.”

He asked NIH to clamp down on any information about him to protect his 6-year-old daughter.

“With the fear and lack of scientific-derived actions in the United States, I was worried she would be shunned by some people who have children at her school,” he said.

“I, therefore, kept my isolation and illness a secret from many friends and colleagues. This was an important decision, but at the same time, it left me isolated from many who I care about.”