It’s YOU! Not the Vaccine that can keep you away from COVID19!!!
According to WHO, there are 42 vaccine candidates that have reached various phases of the clinical stage of development. “The vaccine is coming soon” is what the general mindset is. The question, however, we are facing currently in these worldwide clinical trials, is that will a vaccine be able to control this novel enemy called COVID-19?
Before we get into finding an answer to this question, let’s have a quick background about how vaccines and medicines are tested in humans in various phases. Phase 1 clinical trials involve 20 – 80 healthy subjects testing whether the product is too toxic for humans, and how it gets metabolized in the body. If that is successful, Phase 2 trial is initiated with even more subjects who have the target infection/disease, thereby giving the idea whether the product being tested is effective as well as safe. However, these results of phase 2 are needed to be confirmed in a larger subject population (thousands of subjects) in Phase 3 clinical trials.
Due to the current situation, the testing and approval process for COVID-19 treatment and vaccine candidates has been fast tracked . An expedited approach would mean, not having enough animal studies data and subsequent clinical trial data. It poses a danger of rushing into a decision on moving forward when there are unclear trends on safety and efficacy. The consequences for the fast track approvals could be the increased number of safety issues and exposure of the patients to unnecessary risks. The fast-tracking of the approval process could lead to an increase in the number of product recalls as is the latest case of the proposed recall of a hydroxyl progesterone caproate injection by USFDA.
USFDA CDER has recently proposed that a certain hydroxyl progesterone caproate injection be withdrawn from the market as the required post-marketing assessment study failed to verify clinical benefit. This hydroxyl progesterone caproate injection had received accelerated approval in 2011 to reduce the risk of preterm birth in women who previously had a spontaneous (unexplained) preterm birth.
Phase 3 trials are as important, if not more, as the phase 2 and phase 1 trials, as a larger subject population studied for a longer duration, generates the necessary amount of safety and efficacy data for a marketing approval. The consideration of the benefits against the risks that the patients are exposed to, is the most important one. The recent experiences of the AstraZeneca – Oxford Vaccine trial and Johnson & Johnson vaccine trial, indicate the same.
Earlier in September, AstraZeneca halted its COVID-19 vaccine trial due to a serious adverse event called transverse myelitis in a patient. Transverse myelitis is a serious condition involving inflammation of the spinal cord. The trials are still paused in India, Brazil, USA and South Africa. In a recent turn of events, Johnson & Johnson have also put their COVID-19 vaccine trial on hold, due to an unexplained illness in a participant. Although more details are not available about the illness at the moment, this does establish that a potentially effective vaccine may still get held up because of its safety complications.
According to a report by USFDA team led by Peter G. Lurie (former associate commissioner for public health strategy and analysis at the Food and Drug Administration), 22 detailed case studies of products with promising Phase 2 results were studied. 14 of these featured Phase 3 studies failed to confirm product effectiveness found in Phase 2, one identified a safety issue and seven could not confirm either safety or effectiveness. Five of these 22 were for vaccines; four failed to demonstrate efficacy in their Phase 3 trials, while the fifth failed to prove either safety or efficacy.
Not all the vaccine candidates that have entered phase 2 or phase 3 are going to be successful in clinical trials. Moreover, there is a high possibility of the successful vaccine being effective against only certain strains of the virus. Mutation of the virus and continuous change of the strains may bring all development work back to square one.
We all are rooting for successful vaccines and treatments for COVID-19. But the challenges of mass production and distribution can be greater than the challenges faced in clinical development. The mass production and subsequent supply chain has to be robust enough to support the huge demand. Governments will have a hard time ensuring its reach to all of its affected citizens. A country as big as India will be facing humongous challenge of keeping the vaccine or the treatment affordable for all its citizens. Even if the government tries to shoulder the load with the pharmaceutical companies and provide the vaccine free of cost or at subsidized rates in government hospitals, the financial burden will be huge on an already burdened economy.
The claims that a successful vaccine is just around the corner and will end the deadly pandemic of coronavirus, may not be as real and practical as it seems to be. There is a long road ahead in this fight; and while it is appropriate for the pharmaceutical industry and the governments to prepare for the advent of a successful vaccine, we must continue following the preventive measures and be prepared to rely on prevention of infection by maintaining social distance and wearing of appropriate face masks in the future as well.
