LONDON / CHICAGO (Reuters) – The first wave of the COVID-19 pandemic may fade. For vaccine developers, that can be a problem.
PHOTO FILE: Professor Adrian Hill, Director of the Jenner Institute, and Chief Trial Investigator, conducted an experiment containing the Ebola vaccine at the Oxford Vaccine Group Center for Clinical Vaccine and Tropical Medicine (CCVTM) in Oxford, southern England September 17, 2014. First volunteer in trials Britain’s rapid safety test of the experimental Ebola vaccine made by GlaxoSmithKline received an injection on Wednesday, test organizers said. REUTERS / Steve Parsons / Pool
Scientists in Europe and the United States say the relative success of cruel locking and social distance policies in some regions and countries means the rate of transmission of the virus may be at such a low level that there is not enough disease circulating to actually test a potential vaccine.
They may need to look further, to pandemic points in Africa and Latin America, to get convincing results.
“Ironically, if we really succeed in using public health measures to eliminate hot spots of viral infections, it will be more difficult to test vaccines,” said Francis Collins, director of the National Institutes of Health in the United States.
Vaccines are seen as crucial to ending the pandemic which has killed nearly 370,000 people and infected more than 6 million so far, with world leaders viewing inoculation as the only real way to restart their stalled economy.
But running large-scale clinical trials of potential vaccines against a completely new disease with a very complex pace, scientists say. Showing efficacy in such trials during a fluctuating pandemic adds extra difficulty – and doing so when the outbreak is reduced makes it even more difficult.
“For this to work, people need to have a risk of infection in the community. If the virus has been eradicated temporarily, then the exercise is futile, “said Ayfer Ali, an expert in the reuse of medicines at Warwick Business School in England.
“The solution is to move to an area where infection is spreading widely in society – which will be countries like Brazil and Mexico today.”
Vaccine trials work by dividing random people into the treatment group and the control group, with the treatment group getting an experimental trial vaccine and the control group getting a placebo.
All participants returned to the community where the disease was circulating, and subsequent infection rates were compared. The hope is that infections in the control group will be higher, suggesting vaccine trials protect other groups.
With the COVID-19 epidemic in the UK, mainland Europe and the United States dropping from its peak and transmission rates from coronaviruses declining, the main task for scientists is to pursue fluctuating outbreaks and look for volunteers in some populations or in countries where the disease is still rife.
A similar problem arises when scientists try to test a potential new vaccine against Ebola during the 2014 major outbreak in West Africa. Later, drug makers were forced to drastically reduce plans for large trials because their vaccines were only ready for the final test of the epidemic when the number of cases was reduced. reut.rs/36OmkVu
To track interactive charts of global deployments, open tmsnrt.rs/3aIRuz7 in an external browser
Among the first COVID-19 vaccines that entered phase two, or the middle phase, the trial was one of the biotech companies A. Modern.MRNA.O) and others are being developed by scientists at Oxford University supported by AstraZeneca (AZN.L). The United States plans in July to launch extensive efficacy trials of 20,000 to 30,000 volunteers per vaccine.
Collins said, U.S. health officials will tap into government and industry clinical trial networks in the United States first and use mapping to detect where the virus is most active. They will also consider looking abroad if the level of domestic disease falls too far, he said.
U.S. Government has experience in Africa in testing vaccines against HIV, malaria and tuberculosis.
“Africa is now beginning to experience many cases of COVID-19. We might really want to run part of the trial there, where we know we can collect data effectively, “Collins said.
Adrian Hill, director of the Jenner Institute at Oxford University in the UK in collaboration with AstraZeneca, began testing the mid-stage last month which he said would aim to recruit around 10,000 people in Britain.
He told Reuters that with COVID-19 disease transmission rates decreasing in the UK, there was a possibility that trials would have to be stopped if they did not have enough infections to produce results.
“That will be disappointing, and currently not possible, but certainly a possibility,” Hill said.
Underscoring the level of concern in the industry, AstraZeneca chief executive Pascal Soriot said his researchers were even considering running a so-called “challenge” trial – where participants would be given an experimental vaccine and then deliberately infected with COVID-19 to see if it worked. Such trials are rare, high-risk and difficult to obtain ethical approval.
As a more practical and faster option, Soriot and others are looking to Brazil and other countries in South America, as well as parts of Africa where the COVID-19 outbreak is still growing and peaking, as a place for testing drugs and vaccines that mature.
Candidates recruiting difficulties for mid-stage vaccine trials in countries where the COVID-19 pandemic is diminishing can be predicted by the experience of doctors seeking infected cases for World Health Organization multi-country solidarity trials of various potential treatments for this disease – including generic drugs hydroxychloroquine and Gilead (GILD.O) remdesivir.
In the Swiss part of the trial, for example, it took three weeks to get all ethical approvals and regulations from the authorities, and another week to get all drugs, said Oriol Manuel, infectious disease expert and national Solidarity coordinator. study in Switzerland.
“We can register several patients in (one trial center) Lausanne,” said Manuel. “But when all the centers are ready, fortunately those cases disappear.”
Reported by Kate Kelland in London, Julie Steenhuysen in Chicago and John Miller in Switzerland. Editing by Carmel Crimmins
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