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the science of Covid-19: vaccines and trials in the pipeline

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Experts are still claiming 18 months at best for an effective vaccine, and with reports of re-infection, or resurgent virus activity in supposedly recovered subjects, it has become clear (or seems to have?) that we don’t know quite what we’re dealing with. Which of course poses problems for immunologists.

Still, the race is on. The WHO recently reported ‘more than 5 dozen vaccine candidates being pursued around the world’. The essential reason for the ‘delay’, however, is the three-phase human testing program that has become de rigueur for vaccine development. This video from YourekaScience, made five years ago, goes through the process, and note that it talks about a 6 to 10 year process, sometimes longer. The first phase focuses on safety (e.g. are there notable side-effects?), tolerability (does the vaccine cause pain, if so, what type, how long etc) and immune reaction (does the immune response look like being effective?). Phase 2 will involve larger numbers of volunteers to further test safety, and to determine proper dosage and timing of vaccines for strongest immune response. If all goes well, testing will move to phase 3, the largest trials, in which the drug will be compared with placebo and its ability to prevent infection can be more accurately measured – for example, whether it’s more effective in some sub-groups than others. Efficacy will determine approval, with possible recommendations, positive or negative, for different sub-groups. (I should add, after further reading, that stage 2 trials are often further divided into a and b phases).

So first-step safety tests on individuals have begun, in China, the USA and no doubt elsewhere. China’s vaccine is a version of a genetically engineered product developed against Ebola, while the USA’s different candidates are made from copies of a part of the SARS-CoV-2 genetic code.

Meanwhile, in Western Australia, volunteers are being recruited from the staff of a group of hospitals for an interesting experiment. They will be given the Bacillus Calmette–Guerin (BCG) injection, developed against tuberculosis. The jab is also known to boost immunity to other respiratory infections, and has a long history of safe clinical use. The trial has already been endorsed by the WHO. A similar trial, using healthcare workers, is planned for South Australia.

Australia also has a potential Covid-19 vaccine ready to go into first-phase testing in mid-May. It’s called NVX-CoV2373 (remember that name – or maybe not). Its developer, the biopharma company Novovax Inc, has partnered with Australia’s Nuclear Network, a clinical trials specialist, for the trials. The online mag Biowold reports:

The candidate, NVX-CoV2373, is going to have “a very similar safety profile” to Novavax’s phase III Nanoflu nanoparticle vaccine and, given preclinical findings, appears to be stable and productive, [Gregory Glenn, Novovax president of R&D said]. “The conformation is exactly what you need. And now we’re seeing that manifest after immunizing animals [in which we’re seeing] very, very high neutralizing antibody, which I think everyone would agree is highly likely to be protective,” he added.

Although we may be able, with the sort of effective collaboration this pandemic requires, to reduce the time-frame for a vaccine, reducing the current fatality rate is also a priority, hence the importance of the Australian (and other) trials. We are benefitting from the experience of a host of immunologists and biochemists whose experience has helped us to to look at solutions in this area. An article in The Lancet from a week ago is a good example. The authors suggest that anti-tumour necrosis factor (TNF) therapy is a therapy well worth trying:

Anti-tumour necrosis factor (TNF) antibodies have been used for more than 20 years in severe cases of autoimmune inflammatory disease such as rheumatoid arthritis, inflammatory bowel disease, or ankylosing spondylitis. There are ten (as reported on Sept 29, 2019) US Food and Drug Administration approved and four off-label indications for anti-TNF therapy,4 indicating that TNF is a valid target in many inflammatory diseases. TNF is present in blood and disease tissues of patients with COVID-195 and TNF is important in nearly all acute inflammatory reactions, acting as an amplifier of inflammation. We propose that anti-TNF therapy should be evaluated in patients with COVID-19 on hospital admission to prevent progression to needing intensive care support.

Whether the WHO or national government bodies or private companies take up this proposal is a question, but this is a time when investments of this sort should be made, and the results shared worldwide. This and other pandemics should provide the best opportunity for the kind of collaboration that transcends boundaries and individual reputations. We’ve done inspiring work on so many diseases that once thrived in our own ancestral communities – smallpox, leprosy, cholera, typhoid, scurvy, polio, tuberculosis, measles, whooping cough and many more. Our detailed knowledge of our immune system and how it can be primed and harnessed is distributed in researchers and their writings worldwide. All we need is the collective will and the appropriate collaborative approach to take advantage, for humanity’s sake, of all we’ve learned.



Vaccine Clinical Trials 101: How do we develop and test new vaccines? (video)




Written by stewart henderson

April 15, 2020 at 8:55 pm