The United States posted a record of 53,000 new coronavirus cases as the deadly pandemic accelerated and the nation braced for the July 4 weekend.
Now the epicenter of the pandemic, the country has recorded nearly 129,000 deaths out of more than 2.7 million cases. It is expected to record its three millionth infection next week.
The United States soared past 50,000 new infections Thursday for the second time in two days, casting a grim pall over its upcoming Independence Day celebrations.
Florida, which now has more than 169,000 cases, is a key focus of public health experts who worry about a surge in southern and western US states.
Current COVID strain more potent
The genetic variation of the novel coronavirus that dominates the world today infects human cells more readily than the original that emerged in China, according to a new study published in the journal Cell.
The lab-based research suggests this current mutation is more transmissible between people in the real world compared to the previous iteration, but this hasn’t yet been proven.
Researchers from the Los Alamos National Laboratory in New Mexico and Duke University in North Carolina partnered with the University of Sheffield’s COVID-19 Genomics UK research group to analyze genome samples published on GISAID, an international resource for sharing genome sequences.
They found that the current variant, called “D614G,” makes a small but potent change in the “spike” protein that protrudes from the surface of the virus, which it uses to invade and infect human cells.
Laboratory experiments meanwhile showed that the variant is three to six times more capable of infecting human cells.
“It seems likely that it’s a fitter virus,” said Erica Ollmann Saphire, who carried out one of the experiments at La Jolla Institute for Immunology.
Test monkeys develop temporary immunity
Test monkeys infected with the novel coronavirus responsible for the COVID-19 pandemic were protected from reinfection for up to 28 days later, a Chinese study in the journal Science said.
While the monkeys displayed initial immunity, it’s unclear how long such immunity will last in humans – it will be necessary to wait months, or even years, to know if the millions of people infected at the start of the pandemic are protected from re-infection.
Scientists from Peking Union Medical College performed an experiment on rhesus macaques, often used because of their similarities to humans, to find out if they have a short-term immunity to the virus.
Six rhesus macaques were infected in their trachea with a dose of the SARS-CoV-2 virus. They developed mild to moderate symptoms, and took about two weeks to recover.
The monkeys showed a stronger immune response after the first infection, producing more so-called neutralizing antibodies which may have protected them against short-term reinfection, the scientists wrote.
UK begins lifting quarantine
The British government on Friday revealed the first exemptions from its coronavirus quarantine, with arrivals from Germany, France, Spain and Italy no longer required to self-isolate from July 10.
But in a potentially confusing move, the exemptions – applied to countries considered to have a low risk of COVID-19 – will only apply to arrivals into England.
Those arriving into other parts of the UK – Scotland, Wales or Northern Ireland – will still have to self-quarantine for 14 days, or face a fine.
Britain has suffered the deadliest coronavirus outbreak in Europe, with at least 44,000 dead, but infection rates are falling and it is gradually easing a three-month lockdown.