Covid-19 pandemic: Is there an end in sight? The answer now is ‘yes’

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Covid-19 pandemic: Is there an end in sight? The answer, we now know, is yes. Representational image (Courtesy: The Atlantic)

Covid-19 pandemic: Is there an end in sight? The answer, we now know, is yes. US drug makers Moderna and Pfizer say trials have shown their vaccines are 95 percent effective against the new coronavirus. Many challenges remain, however. Regulators in the US, and elsewhere, still have to approve the new vaccines.

Then, there is the question of supply and demand, as well as how to distribute billions of doses globally. Meanwhile some countries may not even be able to afford them. But could this be the beginning of the end of the fight against the Covid-19 pandemic?

For all that scientists have done to tame the biological world there are still things that lie outside the realm of human knowledge. The Covid-19 pandemic was one such alarming reminder. It emerged with murky origins in late 2019 and found naive, unwitting hosts in the human body.

Even as science began to unravel many of the virus’s mysteries—how it spreads, how it tricks its way into cells, how it kills—a fundamental unknown about vaccines hung over the pandemic and our collective human fate: Vaccines can stop many, but not all, viruses. Could they stop this one?

FDA to scrutinize the vaccines

The answer, we now know, is yes. Pfizer and Moderna have separately released preliminary data that suggest their vaccines are both more than 95 percent effective. It is far more than many scientists expected. However, neither company has publicly shared the full scope of their data.

But independent clinical-trial monitoring boards have reviewed the results. And the FDA will soon scrutinize the vaccines for emergency use authorization. Unless the data take an unexpected turn, initial doses should be available in December.

The tasks that lay ahead — manufacturing vaccines at scale, distributing them via a cold or even ultra-cold chain, and persuading wary Americans to take them — are not trivial, but they are all within the realm of human knowledge.

Scientific uncertainty at the heart of Covid-19 vaccines is resolved. Vaccines work. And for that, we can breathe a collective sigh of relief. “It makes it now clear that vaccines will be our way out of this pandemic,” says Kanta Subbarao, a virologist at the Doherty Institute, who has studied emerging viruses.

Vaccines rely on spike protein

Pfizer and Moderna’s vaccines both rely on the spike protein, as do many vaccine candidates still in development. These initial successes suggest this strategy works; several more Covid-19 vaccines may soon cross the finish line. To vaccinate billions of people across the globe and bring the pandemic to a timely end, we will need all the vaccines we can get.

But it is no accident or surprise that Moderna and Pfizer are first out of the gate. They both bet on a new and hitherto unproven idea of using mRNA, which has the long-promised advantage of speed. This idea has now survived a trial by pandemic and emerged likely triumphant. If mRNA vaccines help end the pandemic and restore normal life, they may also usher in a new era for vaccine development.

The human immune system is awesome in its power. But an untrained one does not know how to aim its fire. That’s where vaccines come in. They present a harmless snapshot of a pathogen, a “wanted” poster, if you will, that primes the immune system to recognize the real virus when it comes along.

Traditionally, this snapshot could be in the form of a weakened virus or a particularly distinctive viral molecule. But those approaches require vaccine makers to manufacture viruses and their molecules, which takes time and expertise. Both are lacking during a pandemic caused by a novel virus.

mRNA vaccines

Both vaccines, from Moderna and from Pfizer’s collaboration with the smaller German company BioNTech, package slightly modified spike-protein mRNA inside a tiny protective bubble of fat. Human cells take up this bubble and simply follow the directions to make spike protein. The cells then display these spike proteins, presenting them as strange baubles to the immune system.

Recognizing these viral proteins as foreign, the immune system begins building an arsenal to prepare for the moment a virus bearing this spike protein appears.

But no one on Earth, until last week, knew whether mRNA vaccines actually do work in humans for Covid-19 pandemic. Although scientists had prototyped other mRNA vaccines before the pandemic, the technology was still new. None had been put through the paces of a large clinical trial. And the human immune system is notoriously complicated and unpredictable.

Vaccines can even make diseases more severe, rather than less. The data from these large clinical trials are the first, real-world proof that mRNA vaccines protect against disease as expected. The hope, in the many years when mRNA vaccine research flew under the radar, was that the technology would deliver results quickly in a pandemic. And now it has.

Good news for elderly

Experts anticipate that the ongoing trials will clarify still-unanswered questions about the Covid-19 vaccines. For example, Ruth Karron, the director of the Center for Immunization Research at Johns Hopkins University, asks, does the vaccine prevent only a patient’s symptoms? Or does it keep them from spreading the virus? How long will immunity last? How well does it protect the elderly, many of whom have a weaker response to the flu vaccine? So far, Pfizer has noted that its vaccine seems to protect the elderly just as well, which is good news because they are especially vulnerable to Covid-19 pandemic.

If the two mRNA vaccines continue to be as good as they initially seem, their success will likely crack open a whole new world of mRNA vaccines. Scientists are already testing them against currently un-vaccinable viruses such as Zika and cytomegalovirus and trying to make improved versions of existing vaccines, such as for the flu. Another possibility lies in personalized mRNA vaccines that can stimulate the immune system to fight cancer.

No end in sight to Covid crisis

Earlier, expressing “appreciation for WHO and partners’ Covid-19 pandemic response efforts”, the UN health agency’s chief Tedros Adhanom Ghebreyesus convened an emergency committee on July 31 which made it clear that there was not yet an end in sight to the public health crisis.

After a full discussion and review of the evidence, the Committee “unanimously agreed” the outbreak still constitutes a public health emergency of international concern (PHEIC). Tedros accepted the advice of the Committee.

‘Once-in-a-century health crisis’

“The pandemic is a once-in-a-century health crisis, the effects of which will be felt for decades to come”, Tedros told the Committee in his opening remarks.

“Many countries that believed they were past the worst are now grappling with new outbreaks. Some that were less affected in the earliest weeks are now seeing escalating numbers of cases and deaths. And some that had large outbreaks have brought them under control.”

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