COVID-19 vaccine: Test subjects to be purposefully exposed to virus

The UK government is backing studies for January 2021 that would involve giving a small number of participants a vaccine candidate, then deliberately exposing them to SARS-CoV-2.

Published: October 20, 2020 at 10:18 am

Test subjects could be exposed to the new coronavirus in controlled settings as early as January, in a bid to speed up vaccine development, officials have confirmed.

The government is backing so-called human challenge studies, whereby a small number of participants who have received a vaccine will be purposefully exposed to COVID-19 to assess the vaccine’s efficacy. It is hoped these studies will help speed up vaccine development.

In the trials, a small number of young and healthy participants – aged 18 to 30 – will be given a coronavirus vaccine candidate, which has previously been assessed in earlier clinical trials.

This group of up to 90 participants will then be exposed to the virus in a controlled environment. They will be carefully monitored to assess how the vaccine works and any possible side-effects.

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Officials said that human challenge trials offer the chance to speed up vaccine development. It is hoped the trials will start in January, with results expected by May 2021, pending approval from regulatory bodies and ethics committees.

The government announced that it is investing £33.6 million to back the studies in partnership with Imperial College London, hVIVO and the Royal Free London NHS Foundation Trust.

The aim of the research will initially be to discover the smallest amount of virus it takes to cause COVID-19 infection in small groups of healthy young people, who are at lowest risk of harm.

The studies will be carried out under strict conditions at the Royal Free Hospital in London and will feature healthy young adults, carefully selected by researchers, who will be compensated for their involvement.

After the initial study, the volunteers will be tracked for a year.

For the many vaccines still in the mid-stages of development, human challenge studies may help pick out the most promising ones to take forward

Professor Jonathan Van-Tam, England’s deputy chief medical officer

The news comes after the government’s chief scientific adviser said it is “unlikely” that a coronavirus vaccine will stop the disease completely.

Sir Patrick Vallance said that only one disease – smallpox – had ever been completely eradicated. Giving evidence to the joint Commons and Lords National Security Strategy Committee, he said that, in future, treating COVID-19 may become more like seasonal flu.

Sir Patrick said that, over the next few months, it will become clear whether there are any vaccines that do protect, and how long for. He added that, while a number of candidates cause an immune response, only phase three trials will indicate whether they stop people from being infected.

“First, for the many vaccines still in the mid-stages of development, human challenge studies may help pick out the most promising ones to take forward into larger phase three trials,” said England’s deputy chief medical officer, Professor Jonathan Van-Tam.

“Second, for vaccines which are in the late stages of development and already proven to be safe and effective through phase three studies, human challenge studies could help us further understand if the vaccines prevent transmission as well as preventing illness.”

“Our number one priority is the safety of the volunteers,” said lead researcher on the human challenge study, Dr Chris Chiu. “No study is completely risk-free, but the Human Challenge Programme partners will be working hard to ensure we make the risks as low as we possibly can.

“The UK’s experience and expertise in human challenge trials, as well as in wider COVID-19 science, will help us tackle the pandemic, benefitting people in the UK and worldwide,” said Dr Chiu.

How can I protect myself from the coronavirus when shopping?

You’ll have seen signs in your local supermarket advising you to keep two metres from others while moving around the store. This is key to reducing your chances of catching the virus while shopping.

The coronavirus SARS-CoV-2 is spread through respiratory droplets that leave our mouth and nose when we cough, sneeze, or sometimes even talk. The droplets sprayed out by an infected person will contain the virus, which could then enter your body via your mouth, nose or eyes (this is why you shouldn’t be touching your face).

Respiratory droplets don’t usually travel more than one metre, so by keeping two metres from others, you’ll reduce the likelihood of being in the firing line. To make it easier to keep your distance, try to shop during off-peak hours, choose a store that’s limiting the number of people who can be inside at any one time, and use self-checkout if you can.

Keeping your hands clean is the other main thing you can do. If possible, wipe the trolley or basket handles with a disinfectant wipe when you arrive at the store. When you get home, wash your hands or use hand sanitiser before and after unpacking your bags.

A US study found that the coronavirus can survive for up to 24 hours on cardboard, and up to three days on hard, shiny surfaces such as plastic, so wiping down your purchases with a disinfectant spray or a soapy cloth before you put them away is another good habit to get into.

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