The Bacille Calmette-Guerin (BCG) vaccine, originally developed for tuberculosis a century ago, is in focus again, with scientists in the UK starting a large-scale trial on frontline health workers to gauge its effectiveness against Covid-19. As part of the global Brace study, the University of Exeter will inoculate around 1,000 healthcare workers since they are more likely to be exposed to the coronavirus. This will help researchers in knowing quickly if the vaccine is effective against Covid-19.
The BCG vaccine joins a handful of drugs like remdesivir and dexamethasone that have been repurposed to treat Covid-19. While most of the drugs have been either found to reduce viral load or cut down the risk of death among severely ill patients, there is still no specific proven treatment for the novel coronavirus yet.
Repurposed drugs, vaccines being used to treat Covid-19:
Bacille Calmette-Guerin (BCG) vaccine
The BCG vaccine, which is normally administered to newborn babies to protect against tuberculosis, is being tested in the UK, Australia, the Netherlands, Spain and Brazil as part of a global trial to see if it can be repurposed to help boost immunity against the novel coronavirus.
Since the BCG vaccine is proven to provide a long-lasting, general boost to the immune system, researchers hope this innate immunity will buy crucial time to develop an effective and safe Covid-19 vaccine, which is likely to be available to the public not before mid-2021.
“BCG has been shown to boost immunity in a generalised way, which may offer some protection against Covid-19,” Reuters quoted Professor John Campbell of the University of Exeter Medical School as saying.
Recent research results: In a study, published in the journal Cell Reports Medicine, scientists found that individuals dosed with BCG vaccine “did not get sick more often, or become more seriously ill” during the pandemic in comparison to those who were not vaccinated. The study, conducted in the Netherlands, also showed that those who received the vaccine did not have more symptoms.
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Remdesivir, an antiviral that was used for the treatment of Ebola and has been repurposed for treatment of Covid-19, has been found to obstruct the viral replication of SARS-CoV-2, basically the stage where the virus creates copies of itself. It was one of the drugs recently used to treat US President Donald Trump.
Recent research results: According to a 1,062-patient study, published in the New England Journal of Medicine, remdesivir treatment has shown to cut Covid-19 recovery time by five days. Moreover, in patients on oxygen support, the drug reduced recovery time by seven days compared with placebo.
Used as an anti-influenza drug, the anti-viral Favipiravir has shown to restrict the multiplication of the virus in the body of the host once it gets inside a host cell, thereby reducing viral load. Favipiravir has been included as a treatment protocol in several countries, including India. In June, Glenmark Pharmaceuticals launched the drug under the brand name FabiFlu, making it the first oral Favipiravir-approved medication in India for the treatment of Covid-19.
Recent research results: A study, published in the journal PNAS (Proceedings of the National Academy of Sciences of the United States of America), recently revealed that high doses of favipiravir given to hamsters significantly reduced SARS-CoV-2 levels in the lungs, improved lung pathology, and reduced virus transmission by direct contact. It must be noted that hamsters are chosen as test subjects because they closely resemble the human body’s reaction to an experimental drug.
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Hydroxychloroquine (HCQ), traditionally used for the treatment of malaria, rheumatoid arthritis and lupus, has gained traction again after Brazilian President Jair Bolsonaro endorsed it, saying the drug helped him recover from a two-week infection. However, several studies have shown that hydroxychloroquine does not work to treat the coronavirus, with the WHO halting their Solidarity trials in May when a Lancet study suggested that the drug has potentially life-threatening effects.
Interestingly, Donald Trump, who had repeatedly touted HCQ as a “game changer” in the fight against Covid-19, himself was not given the drug when he was being treated for the infection. Trump was given an experimental antibody treatment developed by Regeneron, as well as remdesivir and dexamethasone.
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Recent research results: Results of RECOVERY trials in the UK, recently published in the New England Journal of Medicine, revealed that HCQ was no better than usual care in reducing the chances of death in Covid-19 patients. For the trial, 1,561 patients were given HCQ while 3,155 were given a placebo. The study found that 27 per cent of patients in the HCQ group died as compared to 25 per cent in the standard care group in 28 days. Moreover, only 59.6 per cent of patients in the HCQ group were discharged within 28 days while 62.9 per cent recovered in the placebo group.
Coming to India, the Ministry of Health and Family Welfare last month informed the Parliament that it does not have any data to confirm the safety and effectiveness of HCQ when given to healthcare workers. “However, the drug is not recommended for severe cases and those with pre-existing cardiac disease,” the ministry said.
Typically used to treat inflammation, the low-cost, widely-used steroid dexamethasone was the first oral drug authorised by the UK government for Covid-19. Trump was recently treated with dexamethasone after his oxygen levels dropped to 93 per cent, doctors at Walter Reed National Military Medical Center had said. The steroid is used to treat a range of diseases, including rheumatism, asthma, allergies and even helps cancer patients better handle nausea triggered by chemotherapy.
Recent research results: According to research published in the August issue of Journal of Hospital Medicine, it has been found that giving dexamethasone to Covid-19 patients who are not at risk of severe illness could further endanger their health. However, a recent research, published by JAMA Network Open, has found that dexamethasone indeed reduces the number of days patients spend on mechanical ventilation.
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