What if a vaccine is never found ?

As countries lie frozen in lockdown and billions of people lose their livelihoods, public figures are teasing a breakthrough that would mark the end of the crippling coronavirus pandemic: a vaccine.

But there is another, worst-case possibility: that no vaccine is ever developed. In this outcome, the public's hopes are repeatedly raised and then dashed, as various proposed solutions fall before the final hurdle.

Instead of wiping out Covid-19, societies may instead learn to live with it. Cities would slowly open and some freedoms will be returned, but on a short leash, if experts' recommendations are followed. Testing and physical tracing will become part of our lives in the short term, but in many countries, an abrupt instruction to self-isolate could come at any time. Treatments may be developed -- but outbreaks of the disease could still occur each year, and the global death toll would continue to tick upwards.

"There are some viruses that we still do not have vaccines against," says Dr. David Nabarro, a professor of global health at Imperial College London, who also serves as a special envoy to the World Health Organization on Covid-19. "We can't make an absolute assumption that a vaccine will appear at all, or if it does appear, whether it will pass all the tests of efficacy and safety.

"It's absolutely essential that all societies everywhere get themselves into a position where they are able to defend against the coronavirus as a constant threat, and to be able to go about social life and economic activity with the virus in our midst," Nabarro tells CNN.

Most experts remain confident that a Covid-19 vaccine will eventually be developed; in part because, unlike previous diseases like HIV and malaria, the coronavirus does not mutate rapidly.

Many, including National Institute of Allergy and Infectious Diseases director Dr. Anthony Fauci, suggest it could happen in a year to 18 months. Other figures, like England's Chief Medical Officer Chris Whitty, have veered towards the more distant end of the spectrum, suggesting that a year may be too soon.

But even if a vaccine is developed, bringing it to fruition in any of those timeframes would be a feat never achieved before.

"We've never accelerated a vaccine in a year to 18 months," Dr. Peter Hotez, dean of the National School of Tropical Medicine at Baylor College of Medicine in Houston, tells CNN. "It doesn't mean it's impossible, but it will be quite a heroic achievement.

 

"We need plan A, and a plan B," he says.

In 1984, the US Secretary of Health and Human Services Margaret Heckler announced at a press conference in Washington, DC, that scientists had successfully identified the virus that later became known as HIV -- and predicted that a preventative vaccine would be ready for testing in two years.

Nearly four decades and 32 million deaths later, the world is still waiting for an HIV vaccine.

Instead of a breakthrough, Heckler's claim was followed by the loss of much of a generation of gay men and the painful shunning of their community in Western countries. For many years, a positive diagnosis was not only a death sentence; it ensured a person would spend their final months abandoned by their communities, while doctors debated in medical journals whether HIV patients were even worth saving.

The search didn't end in the 1980s. In 1997, President Bill Clinton challenged the US to come up with a vaccine within a decade. Fourteen years ago, scientists said we were still about 10 years away. The difficulties in finding a vaccine began with the very nature of HIV/AIDS itself. "Influenza is able to change itself from one year to the next so the natural infection or immunization the previous year doesn't infect you the following year. HIV does that during a single infection," explains Paul Offit, a pediatrician and infectious disease specialist who co-invented the rotavirus vaccine.

"It continues to mutate in you, so it's like you're infected with a thousand different HIV strands," Offit tells CNN. "(And) while it is mutating, it's also crippling your immune system."

HIV poses very unique difficulties and Covid-19 does not possess its level of elusiveness, making experts generally more optimistic about finding a vaccine.

But there have been other diseases that have confounded both scientists and the human body. An effective vaccine for dengue fever, which infects as many as 400,000 people a year according to the WHO, has eluded doctors for decades. In 2017, a large-scale effort to find one was suspended after it was found to worsen the symptoms of the disease.

Similarly, it's been very difficult to develop vaccines for the common rhinoviruses and adenoviruses -- which, like coronaviruses, can cause cold symptoms. There's just one vaccine to prevent two strains of adenovirus, and it's not commercially available.

 

"You have high hopes, and then your hopes are dashed," says Nabarro, describing the slow and painful process of developing a vaccine. "We're dealing with biological systems, we're not dealing with mechanical systems. It really depends so much on how the body reacts."

Human trials are already underway at Oxford University in England for a coronavirus vaccine made from a chimpanzee virus, and in the US for a different vaccine, produced by Moderna.

However, it is the testing process -- not the development -- that holds up and often scuppers the production of vaccines, adds Hotez, who worked on a vaccine to protect against SARS. "The hard part is showing you can prove that it works and it's safe."

If the same fate befalls a Covid-19 vaccine, the virus could remain with us for many years. But the medical response to HIV/AIDS still provides a framework for living with a disease we can't stamp out.

"In HIV, we've been able to make that a chronic disease with antivirals. We've done what we've always hoped to do with cancer," Offit says. "It's not the death sentence it was in the 1980s."

(CNN)



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