COVID-19 Scientific News — week starting 01/06/2020

5 min readJun 6, 2020

Measures & Models

A systematic review examined 172 observational studies on person-to-person transmission of viral diseases. They find that transmission drops significantly at interpersonal distances of 1 m and, at 2 m or further, infection risk nears zero. Masks, when worn by all parties, were found to be very effective in reducing transmission. Eye protection was also found to confer some benefits. [1]

A sociological study suggests that strategies that encourage the formation of “social bubbles” could confer some of the benefits of social distancing with fewer drawbacks. [2]

Epidemiologists from the US examined different scenarios of SARS-CoV-2 transmission in a 5 year time-frame, using data from seasonal coronaviruses. Regardless of seasonality and in the absence of other interventions i.e. a long-lasting and effective vaccine, intermittent or prolonged social distancing measures will be needed well into 2021 and probably until 2022. The authors also note that even in the event of apparent elimination, SARS-CoV-2 may remain a dormant threat at least until 2024. [3]
Personal note: this is a fascinating study that examines many scenarios, well worth checking out, there are so many details I am not discussing here.

The WHO and independent experts have all cautioned against the idea of an immunity passport. The chief concern is the current lack of understanding of immunity against SARS-CoV-2. A variety of other reasons are also cited. [4,5]

A simple computational model was developed to assess the effect of vaccination on the pandemic. The researchers suggest that in order to stem the pandemic using a vaccine alone, that vaccine would have to provide immunity to at least 70 % of patients and be administered to at least 60 % of the population within 90 days of the initial outbreak. In reality, even a much less efficacious vaccine given much later can be enormously valuable, especially if administered to larger portions of the population. [6]

Therapeutics & Vaccines

A government-funded vaccine development effort from China has reported animal study results. The inactivated virus vaccine raises neutralising antibodies in multiple mammalian species and provides immunity to rhesus macaques challenged with SARS-CoV-2. Notably, the authors demonstrate how to reliably produce their vaccine on scale. [7]

Phase III studies on remdesivir showed that for critical patients, a 5 day course is equally as effective as a 10 day treatment. [8,9]

Tocilizumab (an anti-IL-6 antibody against children’s arthritis) showed a 30 % decrease in mortality compared to patients who did not receive this treatment. These patients did develop superinfections (mostly S. Aureus), but this did not impact their survival rates. [9,10]

A study from China finds that treatment with convalescent plasma was not associated with reduced mortality or faster time to recovery. However, it did result in less severe disease. Notably, the effects are seen in patients with severe COVID-19 but not in those with life-threatening COVID-19, another piece of evidence that the disease displays two phases; first the viral infection is the main culprit, whereas later the inflammatory response is the big problem. [11]

DARPins (synthetic proteins that mimic antibodies; none yet approved for human use) have allegedly been developed that potently inhibit SARS-CoV-2 replication. Onto animal models! [12,13]

Acalabrutinib (BTK inhibitor; BTK is upstream from IL and so may play a role in the cytokine storm) has been prescribed off-label to some patients with severe COVID-19 and has shown some positive effects. Two clinical trials for this drug are registered but not yet recruiting. [14,15]

A randomised, double-blind, placebo-controlled trial in the US and Canada found that use of hydroxychloroquine (HCQ) did not show any protective effects against SARS-CoV-2. Roughly 40 % of patients taking HCQ experienced side-effects. [16,17]

RECOVERY (a trial in the UK with ~11000 patients enrolled) has announced that examination of their HCQ arm displayes no benefits for patients with COVID-19. Some patients in the arm were also receiving zinc. [18,19]

Disease Physiology

An observational study notes that patients with COVID-19 have higher rates of androgenetic alopecia than the general population. In addition, it is known that COVID-19 is disproportionately more frequent and severe in men than women. Given these two facts, the authors postulate that androgen receptors may play a role in disease severity and that anti-androgen treatment may be worth investigating. [20]

More evidence has emerged that the main target of the inflammatory response to COVID-19 involves mainly the blood vessels that cover alveoli in the lungs. Leakage and clotting seem to be prevalent, helping to explain exactly why obesity, diabetes and cardiovascular complications are extremely high risk comorbidities for COVID-19. [21,22]

An analysis of patients who suffered from COVID-19 before operation found that these patients were much more likely to experience pulmonary complications and also had a higher mortality rate. Based on this, it is recommended that non-urgent surgical procedures are avoided during the pandemic. [23]

Testing

Antibody testing studies in China indicate that not all patients with confirmed SARS-CoV-2 infection display both IgG and IgM antibodies within 25 days of infection. This suggests that both types of antibodies should be tested for in seroprevalence studies. [24]

A helpful reference for currently available diagnostic tools for COVID-19 has been published in Science Translational Medicine. [25]

Enable Biosciences has reported excellent antibody testing results (ELISA) using a system of at-home self-collected finger-prick dried blood samples. These samples were collected from volunteers using standard post. This may be a viable way to test populations with minimal exposure risk to healthcare workers. [26]

Corrections

Publications on retrospective studies from the company Surgisphere on HCQ and ivermectin have been withdrawn due to the company being unable to validate their data. These studies can no longer be considered reliable. [27–31]

The withdrawn HCQ study is one I mentioned a couple weeks ago, this piece of news is no longer valid. Even taking this into account, HCQ is still not an effective treatment based on all the other studies showing no benefit. [32]

A retrospective study of patients receiving ACE inhibitors in the New England Journal of Medicine has also been flagged as suspicious. [33]

References

COVID-19 Scientific News — week starting 01/06/2020

Written by Michael Bogdos