They are starting to think the mutations are forming in patients with compromised immune systems and the longer they have the virus the more chance it mutates. Bad news for a lot of HIV and cancer sufferers...among others.
The 45-year-old patient had been sick with coronavirus for months. Doctors had given him the antiviral drug remdesivir to fight the virus, anticoagulation drugs to prevent blood clots, immune modulators to try to control his out-of-control immune response and steroids to fight inflammation.
He'd been home on and off but never seemed able fully recover. His blood oxygen would drop, although tests indicated he was negative for the virus.
It turns out it was just what doctors both knew and feared would happen -- the virus was evolving in the patient's body.
"We sequenced the virus from the first episode, from the second episode, and continued to sequence as the patient was admitted again and again," Li told CNN.
At first, the goal was simply to see if the patient was getting repeated new infections, or had developed a chronic infection with the same virus.
The genetic tests not only showed the man had been infected with the same virus all along, but that it had been evolving as it replicated. "It was incredible," Li said.
Over the next few weeks the patient -- who had an underlying condition that weakened his immunity -- developed a range of symptoms. Five months after he first tested positive, the patient was put on a ventilator to help him breathe. He developed an invasive fungal infection, and died 154 days into his illness.
An autopsy showed his lungs and spleen were laden with virus. And the mutations were especially common in what's known as the receptor binding domain of the spike gene -- which codes for the knob-like structures the virus uses to dock onto the cells it infects.
Looking back, Li says, the resemblance is clear. They're the same mutations that are worrying scientists watching the so-called South African, UK and Brazilian variants known as B.1.351, B.1.1.7 and P.1.
