DNA links man to world's first woman

Houston, Mar 15: Researchers, studying the novel coronavirus, have found that the time between cases in a chain of transmission is less than a week, and over 10 per cent of patients are infected by someone who has the virus, but does not show symptoms yet, a finding that may help public health officials contain the pandemic.

The study, published in the journal Emerging Infectious Diseases, estimated what's called the serial interval of the coronavirus by measuring the time it takes for symptoms to appear in two people with the virus -- the person who infects another, and the infected second person.

According to the researchers, including those from the University of Texas at Austin, the average serial interval for the novel coronavirus in China was approximately four days.

They said the speed of an epidemic depends on two things -- how many people each case infects, and how long it takes cases to spread.

The first quantity, the scientists said, is called the reproduction number, and the second is the serial interval.

Due to the short serial interval of the disease caused by the coronavirus -- COVID-19 -- they said, emerging outbreaks will grow quickly, and could be difficult to stop.

“Ebola, with a serial interval of several weeks, is much easier to contain than influenza, with a serial interval of only a few days,” said Lauren Ancel Meyers, study co-author from UT Austin.

Meyers explained that public health responders to Ebola outbreaks have much more time to identify and isolate cases before they infect others.

“The data suggest that this coronavirus may spread like the flu. That means we need to move quickly and aggressively to curb the emerging threat,” Meyers added.

In the study, the scientists examined more than 450 infection case reports from 93 cities in China, and found the strongest evidence yet that people without symptoms must be transmitting the virus -- known as pre-symptomatic transmission.

More than one in ten infections were from people who had the virus but did not yet feel sick, the scientists said.

While researchers across the globe had some uncertainty until now about asymptomatic transmission with the coronavirus, the new evidence could provide guidance to public health officials on how to contain the spread of the disease.

“This provides evidence that extensive control measures including isolation, quarantine, school closures, travel restrictions and cancellation of mass gatherings may be warranted,” Meyers said.

The researchers cautioned that asymptomatic transmission makes containment more difficult.

With hundreds of new cases emerging around the world every day, the scientists said, the data may offer a different picture over time.

They said infection case reports are based on people's memories of where they went and whom they had contact with, and if health officials move quickly to isolate patients, that may also skew the data.

“Our findings are corroborated by instances of silent transmission and rising case counts in hundreds of cities worldwide. This tells us that COVID-19 outbreaks can be elusive and require extreme measures,” Meyers said.

UN, May 26: Countries could see a "second peak" of coronavirus cases during the first wave of the pandemic if lockdown restrictions were lifted too soon, the World Health Organization (WHO) has warned.

Mike Ryan, the WHO's head of emergencies, told a briefing on Monday that the world was "right in the middle of the first wave", the BBC reported.

He said because the disease was "still on the way up", countries need to be aware that "the disease can jump up at any time".

"We cannot make assumptions that just because the disease is on the way down now that it's going to keep going down," Ryan said.

There would be a number of months to prepare for a second peak, he added.

The stark warning comes as countries around the world start to gradually ease lockdown restrictions, allowing shops to reopen and larger groups of people to gather.

Experts have said that without a vaccine to give people immunity, infections could increase again when social-distancing measures are relaxed.

Ryan said countries where cases are declining should be using this time to develop effective trace-and-test regimes to "ensure that we continue on a downwards trajectory and we don't have an immediate second peak".

Also on Monday, Tedros Adhanom Ghebreyesus, WHO Director-General, said that a clinical trial of hydroxychloroquine (HCQ) on COVID-19 patients has come to "a temporary pause", while the safety data of the the anti-malaria drug was being reviewed.

According to the WHO chief, The Lancet medical journal on May 22 had published an observational study on HCQ and chloroquine and its effects on COVID-19 patients that have been hospitalized, reports Xinhua news agency.

The authors of the study reported that among patients receiving the drug, when used alone or with a macrolide, they estimated a higher mortality rate.

"The Executive Group of the Solidarity Trial, representing 10 of the participating countries, met on Saturday (May 23) and has agreed to review a comprehensive analysis and critical appraisal of all evidence available globally," Tedros said in a virtual press conference.

The developments come as the total number of global COVID-19 cases has increased to 5,508,904, with 346,508 deaths, according to the Johns Hopkins University.

Washington, May 30: President Donald Trump said Friday he would strip several of Hong Kong's special privileges with the United States and bar some Chinese students from US universities in anger over Beijing's bid to exert control in the financial hub.

In a day of concerted action, the United States and Britain also raised alarm at the UN Security Council over a controversial new security law for Hong Kong, angering Beijing which said the issue had no place at the world body.

In a White House appearance that Trump had teased for a day, the US president attacked China over its treatment of the former British colony, saying it was "diminishing the city's longstanding and proud status."

"This is a tragedy for the people of Hong Kong, the people of China and indeed the people of the world," Trump said.

Trump also said he was terminating the US relationship with the World Health Organization, which he has accused of pro-China bias in its management of the coronavirus crisis.

But Trump was light on specifics and notably avoided personal criticism of President Xi Jinping, with whom he has boasted of having a friendship even as the two powers feud over a rising range of issues.

"I am directing my administration to begin the process of eliminating policy that gives Hong Kong different and special treatment," Trump said.

"This will affect the full range of agreements, from our extradition treaty to our export controls on dual-use technologies and more, with few exceptions," he said.

Secretary of State Mike Pompeo on Wednesday informed Congress that the Trump administration would no longer consider Hong Kong to be separate under US law, but it was up to Trump to spell out the consequences.

China this week pressed ahead on a law that would ban subversion and other perceived offenses against its rule in Hong Kong, which was rocked by months of massive pro-democracy protests last year.

US restricts students

In one move that could have long-reaching consequences, Trump issued an order to ban graduate students from US universities who are connected to China's military.

"For years, the government of China has conducted elicit espionage to steal our industrial secrets, of which there are many," Trump said.

Hawkish Republicans have been clamoring to kick out Chinese students enrolled in sensitive fields. The FBI in February said it was investigating 1,000 cases of Chinese economic espionage and technological theft.

But any move to deter students is unwelcome for US universities, which rely increasingly on tuition from foreigners and have already been hit hard by the COVID-19 shutdown.

China has been the top source of foreign students to the United States for the past decade with nearly 370,000 Chinese at US universities, although Trump's order will not directly affect undergraduates.

Critics say Trump has been eager to fan outrage about China to deflect attention from his own handling of the coronavirus pandemic that has killed more than 100,000 people in the United States, the highest number of deaths of any country.

Chuck Schumer, the top Democrat in the Senate, called Trump's announcement "just pathetic."

Eliot Engel, a Democrat who heads the House Foreign Affairs Committee, noted that Trump treaded lightly on Hong Kong during last year's protests as he sought a trade deal with Xi.

"Now, the president wants to shift the blame for his failures onto China, so he's doing the right thing for the wrong reason," Engel said.

Trump's order could also trigger retaliation. China in March expelled US journalists after the Trump administration tightened visa rules for staff at Chinese state media.

Clash at UN

The United States and Britain earlier in the day urged China to reconsider the Hong Kong law during talks at the UN Security Council, where China wields a veto -- making any formal session, let alone action against Beijing, impossible.

The Western allies raised Hong Kong in an informal, closed-door videoconference where China cannot block the agenda.

They said China was violating an international commitment as the 1984 handover agreement with Britain, in which Beijing promised to maintain the financial hub's separate system until at least 2047, was registered with the United Nations.

"The United States is resolute, and calls upon all UN members states to join us in demanding that the PRC immediately reverse course and honor its international legal commitments to this institution and to the Hong Kong people," said US Ambassador Kelly Craft, referring to the People's Republic of China.  

China demanded that the United States and Britain "immediately stop interfering in Hong Kong affairs," saying the law did not fall under the Security Council's mandate.

"Any attempt to use Hong Kong to interfere in China's internal matters is doomed to fail," warned a statement from China's UN mission.

"There was no consensus, no formal discussion in the Security Council, and the US and the UK's move came to nothing," it said.