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The World Health Organisation said on Tuesday that some treatments appear to be limiting the severity or length of the Covid-19 disease and that it was focusing on learning more about four or five of the most promising ones.
The Geneva-based WHO is leading a global initiative to develop safe and effective vaccines, tests and drugs to prevent, diagnose and treat Covid-19. The respiratory illness has infected 4.19 million people around the world, according to a Reuters tally.
"We do have some treatments that seem to be in very early studies limiting the severity or the length of the illness but we do not have anything that can kill or stop the virus," spokeswoman Margaret Harris told a briefing, referring to the body's so-called Solidarity Trial of drugs against the disease.
“We do have potentially positive data coming out but we need to see more data to be 100 per cent confident that we can say this treatment over that one,” she added, saying more research was needed and planned.
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Ms Harris did not name the treatments. Gilead Science Inc says its antiviral drug remdesivir has helped improve outcomes for Covid-19 patients.
Clinical data released last month on remdesivir raised hopes it might be an effective treatment. Several studies looking at combinations of antiviral medicines have also suggested they may help patients fight off the virus.
Results of a trial in Hong Kong released this month showed a triple drug combination of antiviral medicines helped relieve symptoms in patients with mild to moderate Covid-19 infection and swiftly reduced the amount of virus in their bodies.
The trial, which involved 127 patients, compared those given the combination drug, made up of the HIV medicine lopinavir-ritonavir, the hepatitis drug ribavirin, and the multiple sclerosis treatment interferon beta, with a control group given just the HIV drug.
A malaria treatment championed by US president Donald Trump as a "game changer" in the fight against the coronavirus again failed to show a benefit in patients hospitalised with Covid-19, a study this month found.
While the study had certain limitations, doctors reported that the use of hydroxycholoquine neither lessened the need for patients requiring breathing assistance nor the risk of death.
Vaccine
In Geneva, the WHO official sounded a note of caution around expectations for a vaccine, saying coronaviruses in general are “very tricky viruses” that are “difficult to produce vaccines against”.
More than 100 potential Covid-19 vaccines are being developed, including several in clinical trials. The WHO said in April a vaccine would take at least 12 months.
Ms Harris said that the Americas were the current “centre” of the pandemic, although she also noted rising cases in Africa. However, she said the continent had a “big advantage” over other countries with little experience of infectious disease outbreaks.
“They often have very good contact tracing infrastructure and a deep, deep, deep memory and understanding of why we take a new pathogen very, very seriously,” she said, singling out South Africa for its effective testing and contact tracing.
Asked about the reasons for high case loads in the United States and Brazil, Ms Harris said: “Around the world we have seen that the warnings we put out right from the start, very, very early on, were not seen as warnings about a very serious, lethal disease.”
She restated that the WHO, which has come under criticism especially from the United States for its handling of the pandemic, would conduct an “after-action” review that would include a “free and frank” discussion on its performance.
Herd immunity
However the WHO has condemned the “dangerous” concept of herd immunity for Covid-19.
Herd immunity is an epidemiological term usually reserved to describe how the population as a whole is protected from a disease depending on the levels of people vaccinated.
Asked about the concept being applied to the Covid-19 pandemic, the WHO said “no-one is safe until everyone is safe” and it is “dangerous” to think that countries can “magically reach herd immunity”.
Dr Mike Ryan, executive director of the WHO’s health emergencies programme, told a press briefing in Geneva: “Humans are not herds, and, as such, the concept of herd immunity is generally reserved for calculating how many people will need to be vaccinated and the population in order to generate that effect.
“This is a serious disease, this is public enemy number one, we have been saying it over and over and over and over again.”
He said “no one is safe until everyone is safe”, adding: “So I do think this idea that ‘maybe countries who had lax measures and haven’t done anything will all of a sudden magically reach some herd immunity, and so what if we lose a few old people along the way?’ — this is a really dangerous, dangerous calculation.
“And not one I believe most member states are willing to make that arithmetic.
“Responsible member states will look at all their population — they value every member of society and they try to do everything possible to protect health while at the same time, obviously, protecting society and protecting the economy and other things. We need to get our priorities right as we enter the next phase of this fight.”
Dr Maria Van Kerkhove, technical lead of the WHO’s Covid-19 response, said preliminary data from studies has shown that very low levels of the population have actually been infected with the illness.
“There seems to be a consistent pattern so far, that a low proportion of people have these antibodies.
“And that is important, as you mentioned, because you mentioned this word ‘herd immunity’, which is normally a phrase that’s used when you think about vaccination. You think what amount of the population needs to have an immunity to be able to protect the rest of the population?
“We don’t know exactly what that level needs to be for Covid-19.
“But it certainly needs to be higher than what we’re seeing in seroprevalence studies.
“What the sero-epidemiologic studies indicate to us is that there’s a large portion of the population that remains susceptible.” –Reuters/PA