New Scientist Australian Edition 4-Apr-20

YOU will probably have read that there are going to be X thousand deaths from coronavirus in the country you live in. You may also have read that there are going to be an order of magnitude more or fewer deaths. You would be right to be unsure which is correct. It could be any of them, or none. President Donald Trump has been talking about a possible 100,000 to 200,000 coronavirus deaths in the US if his administration “does well” at tackling the virus. In the UK, there has been talk of 20,000 deaths if measures work and 250,000 without restrictions. There has been no shortage of other estimates put forward by people with little experience of epidemiology, some of which come in very low indeed. These calculations, approximations…

IN THE US, the focus of the coronavirus outbreak last week shifted from the West Coast to New York City. As of 30 March, the city of 8.6 million people had 38,087 confirmed cases, which account for more than a quarter of cases in the US, and 914 people had died of covid-19. In one 24-hour period last week, 2000 people were hospitalised in the city. Most of the positive covid-19 test results have been clustered in the boroughs of Queens and Brooklyn. At a press conference on 25 March, New York City mayor Bill de Blasio said these are “numbers I can barely even comprehend… number[s] that would have been unimaginable just a couple of weeks ago”. In Queens, hospitals and emergency rooms have been flooded with critically ill…

RUMOURS circulating on social media suggest that those exposed to more particles of the coronavirus have a higher viral load and become sicker than other infected people. But the relationship between infection and severity may be more complex in covid-19 than in other respiratory illnesses. The average number of viral particles needed to establish an infection is known as the infectious dose. We don’t know what this is for covid-19 yet, but given how rapidly it is spreading, it is probably relatively low – around a few hundred or thousand particles, says Willem van Schaik at the University of Birmingham, UK. Viral load, meanwhile, relates to the number of viral particles carried by an individual and shed into their environment. “The viral load is a measure of how bright the…

IN THE northern hemisphere, as winter ends, cases of seasonal flu dwindle. Could the same happen with covid-19? Flu surges in winter for three reasons. First, the virus is more stable in cold, dry conditions with low levels of ultraviolet light. Second, people spend more time together indoors, which facilitates viral spread. Third, our immune systems may be weakened due to the mild vitamin D deficiency a lack of sunlight can cause. In theory, these factors could also cause the covid-19 virus to dampen down in spring. But we don’t know if this will happen, and the evidence so far is conflicting. In a study posted online in February, researchers at Harvard University looked at the effects of temperature and humidity on the transmission of the virus in China, Thailand, Singapore,…

AS THE world fights to tackle the covid-19 pandemic, a mystery remains: how and when did the virus cross over into humans? Doubt has been cast on the idea that it happened in the Huanan Seafood Market in Wuhan, China, in December, and now researchers are trying to identify the real source of the infection. The hope is that this knowledge could help prevent future pandemics of other new coronaviruses. According to a study of the first 41 people hospitalised with covid-19 published in January (The Lancet, doi.org/ggjfnn), the first case of covid-19 was a man who showed symptoms on 1 December 2019. Unlike the majority of early cases, he had no links to the Huanan Seafood Market. Since then, no one has been able to confirm where he caught…

PEOPLE in Chinese cities usually plagued by harmful air pollution are breathing far cleaner air. Boat‑free canals in Venice, Italy, are clear enough to see fish. And for the quarter of the global population now living under a coronavirus lockdown, a lack of cars and planes has made the world quieter and birdsong more apparent. While there are signs of easing pressure on the environment, no credible environmentalists say the response forced by the pandemic is a solution for the challenges the world faces on climate change, pollution and biodiversity loss. “The crucial thing to observe is this is happening in an unplanned, chaotic way that’s hurting people’s lives. You’d never advocate for such a thing in climate policy,” says Sam Fankhauser at the London School of Economics. One clear…