Fidel Castro, who defied 10 US presidents in his 50 year rule, dies aged 90

Jun 1: The new coronavirus is losing its potency and has become much less lethal, a senior Italian doctor said on Sunday.

"In reality, the virus clinically no longer exists in Italy," said Alberto Zangrillo, the head of the San Raffaele Hospital in Milan in the northern region of Lombardy, which has borne the brunt of Italy's coronavirus contagion.

"The swabs that were performed over the last 10 days showed a viral load in quantitative terms that was absolutely infinitesimal compared to the ones carried out a month or two months ago," he told RAI television.

Italy has the third-highest death toll in the world from COVID-19, with 33,415 people dying since the outbreak came to light on Feb. 21. It has the sixth-highest global tally of cases at 233,019.

However new infections and fatalities have fallen steadily in May and the country is unwinding some of the most rigid lockdown restrictions introduced anywhere on the continent.

Zangrillo said some experts were too alarmist about the prospect of a second wave of infections and politicians needed to take into account the new reality.

"We've got to get back to being a normal country," he said. "Someone has to take responsibility for terrorizing the country."

The government urged caution, saying it was far too soon to claim victory.

"Pending scientific evidence to support the thesis that the virus has disappeared ... I would invite those who say they are sure of it not to confuse Italians," Sandra Zampa, an undersecretary at the health ministry, said in a statement.

"We should instead invite Italians to maintain the maximum caution, maintain physical distancing, avoid large groups, to frequently wash their hands and to wear masks."

A second doctor from northern Italy told the national ANSA news agency that he was also seeing the coronavirus weaken. "The strength the virus had two months ago is not the same strength it has today," said Matteo Bassetti, head of the infectious diseases clinic at the San Martino hospital in the city of Genoa.

"It is clear that today the COVID-19 disease is different."

London, May 20: The current physical distancing guidelines of 6 feet may be insufficient to prevent COVID-19 transmission, according to a study which says a mild cough in low wind speeds can propel saliva droplets by as much as 18 feet.

Researchers, including those from the University of Nicosia in Cyprus, said a good baseline for studying the airborne transmission of viruses, like the one behind the COVID-19 pandemic, is a deeper understanding of how particles travel through the air when people cough.

In the study, published in the journal Physics of Fluids, they said even with a slight breeze of about four kilometres per hour (kph), saliva travels 18 feet in 5 seconds.

"The droplet cloud will affect both adults and children of different heights," said study co-author Dimitris Drikakis from the University of Nicosia.

According to the scientists, shorter adults and children could be at higher risk if they are located within the trajectory of the saliva droplets.

They said saliva is a complex fluid, which travels suspended in a bulk of surrounding air released by a cough, adding that many factors affect how saliva droplets travel in the air.

These factors, the study noted, include the size and number of droplets, how they interact with one another and the surrounding air as they disperse and evaporate, how heat and mass are transferred, and the humidity and temperature of the surrounding air.

In the study, the scientists created a computer simulation to examine the state of every saliva droplet moving through the air in front of a coughing person.

The model considered the effects of humidity, dispersion force, interactions of molecules of saliva and air, and how the droplets change from liquid to vapour and evaporate, along with a grid representing the space in front of a coughing person.

Each grid, the scientists said, holds information about variables like pressure, fluid velocity, temperature, droplet mass, and droplet position.

The study analysed the fates of nearly 1,008 simulated saliva droplets, and solved as many as 3.7 million equations.

"The purpose of the mathematical modelling and simulation is to take into account all the real coupling or interaction mechanisms that may take place between the main bulk fluid flow and the saliva droplets, and between the saliva droplets themselves," explained Talib Dbouk, another co-author of the study.

However, the researchers added that further studies are needed to determine the effect of ground surface temperature on the behaviour of saliva in air.

They also believe that indoor environments, especially ones with air conditioning, may significantly affect the particle movement through air.

This work is important since it concerns safety distance guidelines, and advances the understanding of the transmission of airborne diseases, Drikakis said.

May 30: Warning of the tightrope walk ahead as governments battle the coronavirus crisis, Nobel laureate Peter Charles Doherty has expressed concern about densely populated countries such as India relaxing lockdown norms while also describing a complete shutdown as “an economic and social impossibility”.

The Australian immunologist, who cautioned that the number of COVID-19 cases will rise in the coming days, said the earliest time frame for an effective vaccine “going into large numbers of people” is nine to 12 months.

"If all goes well with testing, we could know if some of the candidate vaccines are both safe and effective as early as September/October. Then, rolling a vaccine out will depend on the type of product and how quickly it can be made, put in vials and so forth," Doherty told PTI in an email interview from Melbourne.

The novel coronavirus, he added, does not change fast like influenza and, from what is known so far, “the same vaccine should work everywhere”.

Doherty, who is with the Department of Microbiology and Immunology at the Doherty Institute, University of Melbourne, won the Nobel Prize for Medicine in 1996 for his discovery of how the body’s immune system distinguishes virus-infected cells from normal ones.

Discussing the lockdown, he said, "If it was purely a matter of hard science, everywhere should stay locked down. But that’s pretty much an economic and social impossibility.”

The expectation, he said, is the numbers will rise and limiting spread will depend on people acting responsibly and the capacity for rapid response and extensive contact testing.

“And in a densely populated country like India I think that it will be very difficult," the scientist said.

Several countries, including India, began relaxing lockdown norms in mid-May despite the WHO’s warning about a second wave. India’s lockdown began on March 25 and has since been extended. The fourth phase ends on Sunday.

Asked whether there are any alternatives to a lockdown, the 79-year-old said, "There is no other option other than closing borders. South Korea, for example, conducted massive, intensive testing and contact tracing in a wealthy country with a very disciplined population. Otherwise, not till we have effective vaccines."

He added that he personally doesn’t see the point of closing borders for people coming in if there’s already a high incidence of disease in the community, “unless it’s to avoid the need to care for them and use scarce hospital beds".

According to Doherty, the coronavirus "is a new virus which has come straight out of nature".

“It (the virus) has moved so rapidly across the world because of people travelling on international planes as well as tourist ships," he added.

The immunologist also warned against the use of hydroxychloroquine to treat COVID-19, and said current and planned trials of the anti-malaria drug should be stopped.

“My understanding is that the use of the drug in severe disease is definitely contra-indicated, but it’s not yet clear whether, if taken under medical supervision, it could have some useful effect if taken early on, or as a preventive. Those trials just haven’t been done properly," Doherty noted.

The Indian Council of Medical Research (ICMR) has backed the use of hydroxychloroquine as a preventive against COVID-19 even after the WHO suspended clinical trials of the drug citing safety concerns.

Asked whether plasma therapy can be an effective treatment for COVID-19, Doherty said, "We lack good properly controlled trials but, especially if the plasma has been tested for antibody levels and there’s evidence of good activity, it could be helpful. If I had the disease and was offered plasma therapy I would certainly accept, but I would not take hydroxychloroquine."

Doherty is also very optimistic about herd immunity developing against the SARS-CoV-2 infection.

"We think that (herd immunity) will cut in and have an obvious effect when, say, 60 per cent of people have been infected. Best hope is to boost herd immunity with a vaccine," he stated.

Herd immunity is a form of indirect protection from infectious disease that occurs when a large percentage of a population has become immune to an infection, whether through vaccination or previous infections.

The number of COVID-19 cases have crossed 5.9 million and the fatalities 3,65,000, according to the Johns Hopkins University on Saturday. 

In India, the death toll has risen to 4,971 and the number of cases to 1,73,763, according to the Union Health Ministry on Saturday.

Several states, including Bihar, Uttar Pradesh, Madhya Pradesh, Jharkhand and Chhattisgarh, have reported a rise in number since lockdown norms were relaxed in early May and migrant workers reached home.

In Uttar Pradesh, for instance, the number of infections rose from around 3,000 on May 4 to 6,532 on May 26. Similarly, Bihar’s numbers increased from around 500 to over 2,700 in the period.