“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.
So, unlike the spike protein on the SARS-CoV-2 virus, HIV lacks an obvious target for a vaccine, he said. And the targets it does have change rapidly and are hidden from the immune system.
Still, despite the effectiveness of the COVID-19 vaccines, the world will probably never be able to eliminate the SARS-CoV-2 virus the way it has eliminated smallpox and has contained measles, Shapiro said.
Once someone is infected with or vaccinated against measles or smallpox, they’re protected for life. But that’s unlikely to happen with viruses like SARS-CoV-2, which is the same family as several common cold viruses that people can catch again and again.
With cancer, too, a key challenge has been what to target.
“The spike protein, for the most part, that’s going to be the same for every single patient. For cancer, we know now that everyone’s cancer is very very different,” said David Braun, a kidney cancer specialist at the Dana-Farber Cancer Institute in Boston.
Cancer is made up of cells that are nearly identical to cells of the body. That’s why chemotherapy can be so devastating – because it can’t tell the difference between healthy cells and cancerous ones and attacks both.
COVID-19 also came at a time when research – including for HIV and cancer – made it feasible to rapidly develop a vaccine, he and others said.
To deliver his HIV vaccine, Barouch spent years engineering a cold virus to carry a vaccine payload into cells without making people sick. He used the same modified adenovirus 26 to deliver his COVID-19 vaccine.
Researchers also learned from the first SARS virus and a related one called Middle East Respiratory virus how to target the spike protein.
And gene sequencing has become fast and cheap enough that the SARS-CoV-2 virus was quickly analyzed and its progress across the world and the variants that develop can be carefully tracked.
These scientific advances among others allowed scientists to develop COVID-19 vaccines in months rather than years. But people shouldn’t forget or take for granted how lucky we are that the virus was so easily dealt with, said Dr. Daniel Griffin, chief of the division of infectious disease at ProHEALTH, a health care provider in New York.
“The idea of vaccines that are 100% or near-abouts at keeping people from dying and in the 90s at keeping you from getting infected,” he said, “this is a whole new paradigm for vaccine efficacy.”
Contact Karen Weintraub at firstname.lastname@example.org.
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