Coronavirus: Why the current pandemic can last for months or years

The world is closing its doors. Places that used to be full of people have become ghost towns, with huge restrictions imposed on our lives: quarantines, school closings, travel restrictions and meeting bans.

It is a global response to a disease unparalleled in recent history. And what everyone wants to know is when all this is going to happen and when, finally, can we continue with our lives?

In Brazil, Health Minister Henrique Mandetta said that the peak of cases should occur until the month of June.

“We are imagining that we are going to work with upward, spiral numbers in April, May, June. We will spend 60 to 90 days of a lot of stress there so that when we get to the end of June, July, we imagine that it will enter the plateau. August, September we should be coming back, as long as we build the so-called immunity of more than 50% of people, ”said Mandetta this week.

In the UK, Prime Minister Boris Johnson said he believes the country can "turn the tide" against the outbreak in the next 12 weeks (that is, in June).

However, even if the number of cases starts to drop in the next three months, we are still far from over.

This tide can take a long time, possibly years.

It is clear that keeping everything closed and not working is not sustainable in the long run, as the social and economic damage would be catastrophic.

What countries need is an “exit strategy”, that is, a way to remove restrictions and get back to normal.

But the coronavirus is not going to go away. If you lift the restrictions that are holding back the virus, cases will inevitably increase.

"We really have a big problem in knowing what the exit strategy is," says Mark Woolhouse, professor of Epidemiology of Infectious Diseases at the University of Edinburgh. "It's not just the UK, no country has an exit strategy."

It is a huge scientific and social challenge.

There are basically three ways to get out of this situation. All of these scenarios would change the virus's ability to spread:

  • Vaccination
  • Sufficient number of people developing immunity through infection
  • Permanently change our behavior and our society

Vaccines (12 to 18 months)

A vaccine must give immunity to a person so that they will not be sick if exposed.

By immunizing enough, about 60% of the population, the virus cannot cause outbreaks, which is the concept known as group immunity.

This week, in the United States, a person received an experimental vaccine after researchers were allowed to skip the usual rules of testing on animals before testing on humans.

Vaccine research is being conducted at an unprecedented rate, but there is no guarantee that it will be successful, and this will require immunization on a global scale.

The best guess is that a vaccine can be ready for 12 to 18 months, if all goes well. It is a long time to wait in the face of unprecedented social restrictions during periods without war.

"Waiting for a vaccine should not be considered a strategy, because that is not a strategy," Woolhouse told the BBC.

Natural immunity (at least two years)

Health officials around the world have tried to prevent the rapid increase in the number of cases. “Flattening the curve”, as they say, is a crucial measure to avoid overloading health services and limit the number of deaths.

The reduction of cases may allow some restriction measures to be suspended for a while, until cases increase and another round of restrictions is necessary.

When that could happen is uncertain. The UK's leading scientific adviser to the UK, Patrick Vallance, said "it is not possible to set absolute deadlines".

This scenario could, unwittingly, lead to group immunity, as more and more people would be infected. The so-called group immunity became better known after the British government was criticized for its strategy of managing the spread of the infection to make the population immune.

And that scenario could take years to happen, according to Professor Neil Ferguson, from Imperial College London.

“We are talking about reducing transmission to a level where, we hope, only a very small fraction of the country is infected. So, if we continue for more than two years, perhaps a sufficient fraction of the country at that time may have been infected to provide some degree of protection for the community. ”

But there is doubt about whether that immunity could last for a long time. Other coronaviruses, which cause common cold symptoms, lead to a very weak immune response and people can catch the same virus several times in their lives.

Alternatives (no clear deadline)

"The third option is: permanent changes in our behavior that will allow us to keep transmission rates low," said Woolhouse.

This may include maintaining some of the measures that were implemented during the crisis. Or introduce rigorous testing and isolation of patients to try to monitor any outbreaks.

“We did early detection and contact tracking the first time and it didn't work,” adds Woolhouse.

The development of drugs that can successfully treat a covid-19 infection could also help with other strategies.

These drugs could be used as soon as people experience symptoms, in a process called "transmission control", to prevent them from passing on to others.

Or they could be used to treat patients in the hospital to make the disease less deadly and reduce pressure in intensive care. This would allow countries to deal with more cases before they need to reintroduce drastic blocks.

Increasing the number of intensive care beds would have a similar effect, by increasing the ability to deal with larger outbreaks.

Asked what his exit strategy would be, UK chief medical consultant Chris Whitty said: "In the long run, clearly a vaccine is a way out of this and we all hope it will happen as soon as possible."

And he stated that “globally, science will present solutions”.

Source: BBC News Brasil

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