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China's efforts to contain the coronavirus outbreak by quarantining millions are unprecedented. But experts say if they fail, the global ramifications could be catastrophic.

An estimated 50 million people are under quarantine in China's central Hubei province. While there is hope for a downward trend in the number of cases, the unforeseen consequences of the quarantines have called their effectiveness into question.

"I don't think the quarantine was warranted in China," said Dr. Amesh Adalja, an infectious disease physician and a senior scholar at the Johns Hopkins Center for Health Security .

"It probably is going to end up having a paradoxical negative impact, as it isolated the outbreak zone and made the situation worse there while sowing distrust among public health authorities and making it more logistically hard to get supplies there."

Adalja said the fact that quarantines were put in place weeks after the outbreak began is another reason why he believes they are ineffective in slowing the spread of the coronavirus.

The first patient to develop symptoms of coronavirus fell ill in early December and had no contact with the seafood market in Wuhan where the outbreak is thought to have begun, according to a study of cases published in The Lancet late last month.

A medical staff member takes samples from a person to be tested for the new coronavirus at a quarantine zone in Wuhan on Tuesday. One expert says the quarantine was likely put into place in China too late to be effective. (STR/AFP/Getty Images)

"He contracted that illness in November. So that virus had been circulating in the outbreak zone for some weeks before it was noticed," Adalja said.

"It's unlikely that this was ever really restricted to the outbreak zone and that there were likely patients all over China that had mild illness that may have been misdiagnosed or mixed in with other flu and respiratory illnesses."

Jason Kindrachuk, an assistant professor and Canada Research Chair in emerging viruses at the University of Manitoba, said infectious disease experts are starting to lose faith in the effectiveness of the quarantine efforts.

"I think we're getting more concerned. I think before we thought, 'OK, there was a chance to contain it,'" he said.

"Ultimately, it limits the transfer of medical supplies and goods into the region … and we're starting to see that once one domino starts to fall, it actually starts to affect everything."

What if the coronavirus spreads worldwide?

Ninety-nine per cent of coronavirus cases are contained within China. Of those, 80 per cent are in Hubei, the World Health Organization Director-General Dr. Tedros Adhanom Ghebreyesus said Wednesday.

"The relatively small number of cases outside of China gives us a window of opportunity to prevent this outbreak from becoming a broader global crisis," he said.

"Our greatest concern is about the potential for spread in countries with weaker health systems and who lack the capacity to detect or diagnose the virus. We are only as strong as the weakest link."

We are only as strong as the weakest link. - WHO Director-General Dr. Tedros Adhanom Ghebreyesus

Tedros said WHO's current focus is on supporting the Chinese government to address the outbreak at its epicentre in Wuhan.

But developing nations worldwide could be at particular risk if quarantine efforts fail in China due to their fragile health care networks and funding deficits. Other ongoing disease outbreaks like Ebola may also exacerbate their ability to respond effectively.

Cambodia, India, Malaysia, Vietnam, Sri Lanka and Nepal have already recorded cases. One death has also been recorded in the Philippines — a 44-year-old man who had travelled there from Wuhan.

Adjala expects the coronavirus to have a high "attack rate" in different countries, because people there will not have any immunity.

"Not all of those patients are going to be critically ill, but they all are going to take up resources and lead to crowding in hospitals," he said.

The possibility that the virus could spread to African nations is also of major concern.

Dr. Mike Ryan, the World Health Organization's (WHO) top emergencies expert, said at a media briefing Wednesday that as of Feb. 3, only two African nations — Senegal and South Africa — could diagnose coronavirus, but most would have the ability as of Friday.

"Countries that don't have the public health infrastructure, on one hand, potentially have an issue with additional introductions that may go unnoticed," said Dr. John Brownstein, a Harvard medical professor, epidemiologist and chief innovation officer at Boston Children's Hospital.

"And then, of course, that represents the opportunities for movement to other places where people can't predict."

A doctor talks with a patient during his rounds at the ward of a quarantine zone in Wuhan on Monday. One expert says the novel coronavirus will have a high 'attack rate' if it spreads in other countries. (STR/AFP/Getty Images)

Kindrachuk, who worked on the ground in West Africa during the Ebola outbreak in Liberia, says there is reason for concern.

"There is still a high incidence of respiratory illness and respiratory complications in the general populace in a lot of these regions," he said.

"Even things like influenza are still a massive burden."

But Kindrachuk says the coronavirus is being taken seriously by health officials throughout Africa and that many countries are more prepared now than they were before the Ebola outbreak.

"They know what's going on. They're plugged in. They are looking for updates from the African CDC and from the WHO," he said.

"I don't want to say that they're going to be absolutely fine, but I think that they're doing everything that they can do to be prepared."

What else can be done to stop the spread?

The WHO has stressed the need for global "solidarity" to address the spread of the coronavirus and is asking for $675 million US in funding for the next three months.

"Invest today, or pay more later," Tedros said at a press briefing Wednesday. "[It] is a lot of money, but it's much less than the bill we will face if we do not invest in preparedness now during the window of opportunity that we have."

If that window of opportunity is missed, there is the possibility of the virus becoming endemic — something that re-emerges on a seasonal basis.

Adalja says the new coronavirus would then join four others that regularly circulate worldwide — OC43 and 229E , HKU1 and NL 63. Their symptoms include the common cold, pneumonia and upper respiratory infections.

"When you look at the trajectory of the outbreak with the novel coronavirus, it appears that it is also following a kind of seasonal virus pattern," he said.

"We're at the point where you have to think that there is a real possibility that this virus may end up spreading in the community in a manner that's similar to the other coronaviruses."

A medical staff member talks on her phone as she organizes transferring patients in Wuhan on Jan. 26. Many developing countries are still struggling to treat influenza; experts fear coronavirus could overwhelm them. (STR/AFP/Getty Images)

Influenza kills an estimated 290,000 to 650,000 people worldwide per year. Kindrachuk says that too often, the general public considers it a relatively mild disease.

"But are we ready as a global population to be able to take on something that has that big of an effect on our healthcare networks?" he said.

"All we can do is try and increase our ability to be prepared and be responsive and also understand that we're linked as a global community now — whether you like it or not."

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