Covid-19 news: Results from world’s first human challenge trial

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A student takes a lateral flow test in London

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Latest coronavirus news as of 12.30pm on 2 February

Study that infected young adults with the coronavirus finds virus may largely be shed from nose

A small trial that involved deliberately infecting volunteers with the virus that causes covid-19 has revealed new details on how it can cause mild to moderate symptoms. 

This type of research is known as a human challenge trial, and while similar studies have been conducted for various viruses over the years, this is the first to report findings on the coronavirus. 

Researchers in the UK gave 36 volunteers aged between 18 and 29 a low dose of the virus via droplets placed in the nose. The virus was taken from a person who became ill with covid-19 very early in the pandemic, before any notable variants had emerged. 

Eighteen of the volunteers became infected with the virus, and 16 of them developed cold-like symptoms, such as a runny rose, sore throat, cough, fever or headache. Many of these symptoms were not included on symptom lists published by health authorities early in the pandemic. Thirteen of the volunteers also temporarily lost their sense of taste and smell. 

Among those who became infected, the virus could be detected, and symptoms began to develop, within 42 hours. This incubation period is significantly shorter than estimates at the time, which put the incubation period between two and 14 days.

The virus could be detected in the throat at 40 hours, before it could be detected in the nose at around 58 hours. Peak levels of the virus were found to be higher in the nose, suggesting that more virus may spread this way – and highlighting the importance of ensuring face coverings shield the nose as well as the mouth.

Other findings from the study support the use of lateral flow tests in picking up infectious cases of the disease. “We found that overall, lateral flow tests correlate very well with the presence of infectious virus,” Christopher Chiu at Imperial College London, the trial’s chief investigator, said in a statement. “Even though in the first day or two they may be less sensitive, if you use them correctly and repeatedly, and act on them if they read positive, this will have a major impact on interrupting viral spread.”

None of the volunteers developed any serious symptoms and no damage was seen in their lungs. 

Other coronavirus news

Pfizer and BioNTech have begun a process that may eventually allow for the vaccination of children against covid-19 in the US aged between six months and four years. The Pfizer/BioNTech vaccine was first rolled out in the US under an Emergency Use Authorisation or EUA. The US Food and Drug Administration approved the vaccine for adults over the age of 16 in August last year.

The vaccine is currently available for children aged five and older in the US under an EUA, but those under five are not eligible for vaccination. Pfizer and BioNTech expect to complete an EUA submission for six-month to four-year-olds within days.

Tonga is set to enter lockdown following the confirmation of five cases of covid-19 in the country. The cases were identified among two port workers and their relatives. 

The cases represent the first instance of community transmission in the country. Until now, only one case had ever been reported – in a quarantined traveller arriving in the country in October 2021. 

Essential information about coronavirus

Where did coronavirus come from? And other covid-19 questions answered

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Covid-19 vaccines: Everything you need to know about the leading shots

Long covid: Do I have it, how long will it last and can we treat it?

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Covid-19: The story of a pandemic

What to read, watch and listen to about coronavirus

New Scientist Weekly features updates and analysis on the latest developments in the covid-19 pandemic. Our podcast sees expert journalists from the magazine discuss the biggest science stories to hit the headlines each week – from technology and space, to health and the environment.

The Jump is a BBC Radio 4 series exploring how viruses can cross from animals into humans to cause pandemics. The first episode examines the origins of the covid-19 pandemic.

Why Is Covid Killing People of Colour? is a BBC documentary, which investigates what the high covid-19 death rates in ethnic minority patients reveal about health inequality in the UK.

Panorama: The Race for a Vaccine is a BBC documentary about the inside story of the development of the Oxford/AstraZeneca vaccine against covid-19.

Race Against the Virus: Hunt for a Vaccine is a Channel 4 documentary which tells the story of the coronavirus pandemic through the eyes of the scientists on the frontline.

The New York Times is assessing the progress in development of potential drug treatments for covid-19, and ranking them for effectiveness and safety.

Humans of COVID-19 is a project highlighting the experiences of key workers on the frontline in the fight against coronavirus in the UK, through social media.

Belly Mujinga: Searching for the Truth is a BBC Panorama investigation of the death of transport worker Belly Mujinga from covid-19, following reports she had been coughed and spat on by a customer at London’s Victoria Station.

Coronavirus, Explained on Netflix is a short documentary series examining the coronavirus pandemic, the efforts to fight it and ways to manage its mental health toll.

COVID-19: The Pandemic that Never Should Have Happened, and How to Stop the Next One by Debora Mackenzie is about how the pandemic happened and why it will happen again if we don’t do things differently in future.

The Rules of Contagion is about the new science of contagion and the surprising ways it shapes our lives and behaviour. The author, Adam Kucharski, is an epidemiologist at the London School of Hygiene and Tropical Medicine, UK, and in the book he examines how diseases spread and why they stop.

Previous updates

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NHS staff join protesters in London, England

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1 February

Vaccinations will not be a condition of employment for NHS workers in England

NHS staff in England will not be required to have coronavirus vaccinations, health secretary Sajid Javid announced yesterday. The move will be subject to a government consultation.

Regulations for mandatory vaccines were due to come into effect for NHS staff on 1 April which would have made 3 Feb the last day an unvaccinated worker could start a course of vaccinations.

Javid says mandatory vaccines are now less important because omicron, which is currently the dominant variant, appears to be more transmissible and less severe than the earlier delta variant. “It’s only right that our policy on vaccination as a condition of deployment is reviewed,” Javid said. 

Austria has moved in the opposite direction, as its policy of mandatory jabs for all over-18s comes into effect today. It is the first European Union country to impose such a mandate.

Other coronavirus news

Denmark today became the first EU country to lift all of its coronavirus restrictions, despite daily cases of between 40,000 to 50,000, or 1 per cent of its population. Denmark’s health authorities hope that its high vaccination rates of about 81 per cent will prevent a spike in hospitalisations.

Russia has seen its highest daily total for new coronavirus cases, reporting 125,836 on 1 Feb. Unlike Denmark, Russia has relatively low vaccination coverage, estimated at around 50 per cent.

World leaders continue to contract the virus: Canada’s prime minister Justin Trudeau yesterday announced he has tested positive for coronavirus, while UK foreign secretary Liz Truss also said she had tested positive, hours after speaking to a packed House of Commons without a mask.

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A police officer stands guard inside the closed-loop bubble to protect against the spread of covid-19 at the Beijing Winter Olympics

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31 January

Athletes and staff are testing positive for covid ahead of February’s games

About 119 people at the Winter Olympics – including both athletes and staff – have tested positive in Beijing, China, in the last four days. 

The games will run from 4 February to 20 February and about 3000 people, such as athletes and officials, are expected to take part. 

Unlike many countries, China is trying to eradicate covid-19 completely within its borders. It has cancelled nearly all international flights.

Olympic staff and athletes cannot move freely in public during the games. Instead they are living in a “closed-loop” bubble set up by the government which will allow them to train, travel and work without interacting with anyone from outside the event. 

Other coronavirus news

Spotify will add advisory labels to podcasts on its platform that discuss the coronavirus, its chief said yesterday in a statement. Daniel Ek said the new warnings would redirect listeners to a data hub of coronavirus facts. 

Thousands in the UK are set to gain access to Pfizer’s covid-19 antiviral pill from 10 February. The pill, Paxlovid, will be given to high-risk patients – such as those who have cancer or are immunocompromised – if they test positive for coronavirus. 

Trials suggest that the drug can cut the risk of hospitalisation and death by about 88 per cent in high-risk patients  – if administered within five days of symptoms appearing. 

Latest about coronavirus from New Scientist

What you need to know about the fast-spreading BA.2 omicron variant


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