FILE PHOTO: Small bottles labeled with a “Vaccine COVID-19” sticker and a medical syringe are seen in this illustration taken taken April 10, 2020. REUTERS / Dado Ruvic / Illustration / File Photo
London / Chicago (Reuters) – The first wave of the coronavirus pandemic appears to be subsiding. What makes everyone easier is a problem for vaccine developers.
Scientists believe that the lockdown and distance rules in some countries could lead to transmission rates so low that tests with potential vaccines are made more difficult – there are simply too few infected people who could infect others to check the effectiveness of the vaccines. To get meaningful results, scientists may need to focus on the new pandemic hotspots in Africa and Latin America. “Ironically, the more successful the virus containment measures are, the more difficult it will be to test a vaccine,” said Francis Collins, director of the National Institutes of Health (NIH), United States Department of Health.
So far, there is no vaccine against the novel corona virus, which has infected almost 6.3 million people worldwide and has so far claimed around 375,000 lives. An effective vaccine is a prerequisite for a quick end to the pandemic. But large clinical trials with vaccines against a completely new disease are very complicated. The less the virus spreads, the more difficult it is to prove the effectiveness of agents. “For this to work, people in a community must be at risk of infection. If the virus temporarily disappears, the exercise is futile, ”said Ayfer Ali, a scientist at Warwick Business School in the UK.
“The solution is to focus on areas where the virus is widespread, currently that would be countries like Brazil and Mexico,” she says. In vaccine studies, part of the participants receive the vaccine and part a placebo. The hope is that the infections in the control group will be higher, showing that the vaccine will protect the other group. It is therefore one of the key tasks for scientists to find volunteers for studies in regions where the virus is still widespread. The Brazilian Ministry of Health said it was in talks with various vaccine developers about participating in clinical trials. After the United States, the country is the country with the most corona infections worldwide.
TEN THOUSANDS OF VOLUNTEERS WANTED
Similar problems have already been encountered when testing a new vaccine against the Ebola virus during the great outbreak in West Africa in 2014. At that time, major drugmakers were forced to significantly curtail their plans for large studies because their vaccines were only ready for testing at a late stage of the epidemic, when the number of cases declined. One of the first Covid-19 vaccines to be entered into the second phase of clinical development is that of the US biotech company Moderna. The company launched the first volunteer vaccine trial in the United States in March. Another vaccine candidate is being developed by the University of Oxford with the pharmaceutical company AstraZeneca.
The U.S. is planning extensive efficacy studies with 20,000 to 30,000 volunteers per vaccine in July. They want to focus on overseas when home infection rates drop too far, as NIH director Collins says. “There are now many cases of Covid-19 in Africa. We may want to run part of the study where we can effectively collect data. ” Oxford University aims to get 10,000 people together for its study in the UK. If the transmission rates decrease, it is possible that this study must be stopped. “That would be disappointing and currently unlikely, but it is certainly an option,” said Adrian Hill, director of the Jenner Institute.