RIO DE JANEIRO, BRAZIL – At least 70 percent of Brazilians need to be immunized before we can start talking about an end to the Covid-19 epidemic in the country. Reaching this percentage will only be feasible after the majority of the population has been infected and cured.
The alternative is to have a vaccine, which will almost certainly not reach the market before the end of the year.
To anticipate how or when we will reach this level is an exercise in futurology. There is no precedent in recent human history for the current crisis, thus, one cannot look at past events in search of answers. Some studies, however, try to look to the future and point out potential avenues.
A consensus among experts is the adoption of social distancing for a long period to slow the increase of cases. “There is still no way to assess whether the measures being implemented will produce the required effects,” says Roberto Kraenkel, a specialist in epidemiological modeling at the São Paulo State University (UNESP).
“But projections made for other countries suggest the need for lockdown (total isolation of cities, with maintenance only of essential services) for at least two months”.
Estimates by experts from the Pontifical Catholic University of Rio (PUC-Rio) and Fiocruz point out that, by Monday, the country should record 6,375 cases – a number that may vary between 3,555 (optimistic scenario) and 11,548 (pessimistic scenario). It is expected that the total number of cases will start to increase exponentially this week until the effects of social distancing measures begin to be felt.
If more drastic measures are not followed – or are suspended, as suggested by President Jair Bolsonaro – the epidemic in Brazil may follow the same path as the infection in Italy and Spain, which already total 14,200 deaths. In these countries, the number of cases has grown faster than the health system’s capacity to absorb patients.
The concept of reducing the economic impact of mitigation strategies and isolating only the most vulnerable (elderly and chronically ill, for instance), as proposed by Bolsonaro, has been advocated by other world leaders. Italy itself contemplated the strategy at the outset of the epidemic. Soon, faced with the explosion of cases and deaths, it changed its mind.
The United Kingdom’s Prime Minister, Boris Johnson, also had to reverse course. A study by the Imperial College of London on March 16th prompted the British leader to back down. The study projected 250,000 deaths in the country if only softer isolation measures were adopted.
As for Brazil, researchers at Imperial College, led by Neil Ferguson, point out that a social isolation strategy of keeping only the elderly at home could lead to the death of over 529,000 people. The number is half of what is projected for a scenario where nothing would be done to contain the coronavirus (1.15 million deaths). But it is much higher than the estimate for rapid and widespread social isolation. Despite this drastic restriction, there would be at least 44,000 deaths.
“If the isolation and containment measures proposed by the states are respected, we can consider a growth similar to that of France (the country confirmed the 1st case in January. Today, it counts 33,540 patients and 1,900 deaths),” said Silvio Hamacher, of PUC-RJ, a member of the Health Operations and Intelligence Center (NOIS) two days ago. [The numbers in France as of March 29th are 40,174 cases and 2,606 deaths.]
According to researchers at Imperial College, in order to have a sustained effect, the strategy would need to continue for many months. Ideally, until the development of the vaccine or the so-called herd immunization, when the majority of the population has already been contaminated. According to the group’s estimates, it would even be possible to suspend isolation from time to time, but very soon, so as not to make way for new outbreaks.
China
With the pandemic still in progress, those who have already experienced the acute stage provide additional guidance. Some three months after the epidemic officially erupted, China is only now beginning to reopen the Hubei province, where Wuhan is located, but the city that is the epicenter of the novel coronavirus is still to remain closed for another two weeks.
Biologist Fernando Reinach, says that following the unfolding of Wuhan’s reopening will be crucial to understanding how the epidemic will behave. In his opinion, for the time being, the only path that seems safe to prevent many deaths is to contain the population.
The other path, he says, would be to do as South Korea does, testing the population en masse and taking swift action to contain when infected patients emerge and track their contacts in order to avert further spread.
Source: Infomoney