Effective COVID-19 vaccines were developed in under a year. But a half-century after the country declared war on cancer, and 40 years after the first reported case of HIV/AIDS, there remains no way to prevent either disease, or many more.
Why? Biology and timing, scientists say.
How was it possible to develop effective COVID-19 vaccines in less than a year when after decades of trying there remains no way to prevent cancer or HIV/AIDS and many other deadly diseases?
COVID-19 and the virus that causes it were simply easier targets, according to a number of experts, and came along at a time when scientists well prepared to respond.
"COVID-19 can lead to very, very serious illness and can spread rapidly and therefore cause a global pandemic – but in terms of the immune system, it's actually kind of wimpy," said Dr. Dan Barouch, who helped develop Johnson & Johnson's COVID-19 vaccine from his lab at Harvard University.
The human immune system can easily eliminate COVID-19, while none of the 38 million people infected with HIV over four decades has ever completely gotten rid of that virus on their own, said Barouch, who has been working on an HIV vaccine for more than 16 years.
"That virus has developed its own tricks to evade the immune system so the normal human body cannot eliminate it, and also it makes vaccine development very, very difficult," he said of HIV. "It's fundamental scientific differences."
SARS-CoV-2, which causes COVID-19, is a pretty standard virus made of a single strand of genetic code and dotted on the outside with the spike protein that gives the coronavirus family of viruses its distinctive crowned profile.
The HIV virus, by contrast, has a smoother surface, said Dr. Roger Shapiro, an infectious disease clinician at the Harvard T.H. Chan School of Public Health.
"On the surface of HIV it's much more barren," he said, meaning it has fewer targets for vaccine developers to take aim.
And the targets HIV does have are shrouded from the immune system, Shapiro said.
While COVID- goes after certain cells that line the lungs, among other places, HIV attacks the immune system itself, he said. "The very cells that are meant to protect us are the ones targeted by HIV."
Plus, HIV mutates much faster.
"The variation we talk about in COVID is nothing compared to the variation we see with HIV," Shapiro said. Imagine all the variants people are worried about with COVID-19 and more happening within a single person.
