The scientific news of COVID-19 v 1.0
An in-depth pulmonary histopathological analysis of rhesus macaques innoculated with SARS-CoV-2 shows parallels with humans and establishes this as a relevant and validated animal model. [1] Rhesus macaques were infected with SARS-CoV-2, developed antibodies, recovered and re-infection with SARS-CoV-2 was attempted. The animals were protected against the virus and an immune response was mounted. This is the first piece of evidence we have that developing antibodies provides immunity. [2]
Sinovac’s inactivated virus vaccine was shown to be effective in mice, rats and rhesus macaques. [3] Moderna has announced positive results in humans with their mRNA vaccine, however the data is yet to be released. Notably, no approved mRNA vaccine exists yet. [4,5] A spike DNA vaccine from Harvard also provides rhesus macaques with immunity. [6] Innovio’s DNA vaccine raises antibodies in mice and guinuea pigs, however the vaccinated animals were not re-infected in this study. [7] DNA vaccines are used in veterinary medicine, but no such vaccines have been approved yet for humans. [8] Oxford’s adenovirus vaccine also provides macaques with immunity. [9] There has been some back and forth between the scientists at Oxford and critics, with valid points raised by both sides, clinical trials will be the final judge. [10–12] An adenovirus vaccine from China has completed Phase I and was shown to be safe. It induces high and dose-dependent levels of neutralising antibodies against SARS-CoV-2, an encouraging sign. However, patients who had pre-existing antibodies against adenovirus did not effectively seroconvert, showing a potential problem with this approach. [13]
A case study of fitness dance classes from South Korea published by the CDC shows how settings like these can serve as hotspots for infection. This suggests caution when it comes to reopening gyms and related facilities. [14]
When comparing the lungs of deceased patients with SARS-CoV-2 and influenza, who showed similar levels of disease severity. Significantly higher levels of thrombosis (blood clotting) and alveolar capillary damage are seen. This potentially suggests that COVID-19 may cause more lung damage than influenza even when comparing cases with similar levels of disease severity. [15] More postmortem evaluations validate these findings and also note no CNS involvement of SARS-CoV-2. [16] A machine learning model has been developed which can identify patients with COVID-19 based on CT scans as well as a human specialist. [17]
Spain, Italy, Sweden, Denmark and Norway have all reported prevalence of antibodies. All report between 1 and 5 %, a really long way from the 60–70% required for herd immunity. True values are likely different due to the tests used, however the error margin of 1400% needed to reach the herd immunity levels is pretty much impossible. [18–23] Data from the UK reports 24 % of healthcare workers show evidence of antibodies. Notably, < 50 % of symptomatic workers seroconverted. [24]
The data from the NIH remdesivir trial are finally released. In summary, the drug helps patients not on ventilators to recover faster. Serious adverse effects reported for ~1 in 5 patients and mortality not reduced. [25] In China, treatment of severe patients with remdesivir found no benefit and also observed adverse effects. [26]
Human to animal transmission has been confirmed, with findings of SARS-CoV-2 in two dogs in China. It is not yet known whether the animals can transmit back to humans or to other animals. No symptoms were detected in the dogs. [27] This was also observed in minks (Netherlands). [28]
A large international retrospective study (96 k patients) of chloroquine and hydroxychloroquine and their combinations with macrolide antibiotics (azythromycin, clarithromycin) shows no benefit in the outcome or time of recovery for patients with less severe COVID-19 who received treatment early. Significant cardiac effects were seen, as was increased mortality, though the latter is not due to the cardiac events. [29,30] A retrospective study from NY finds a correlation for discharge to home and a therapy of zinc sulfate, hydroxychloroquine and azithromycin for particular patient populations with particular therapy timing. The authors suggest further investigations and do not recommend this therapy yet. [31,32] The original French study touting the benefits of hydroxychloroquine has been retracted. [33] A Chinese study that also finds benefits is fraught with several flaws. [34–36]
Evidence continues to show up that SARS-CoV-2 kicks off a severe immune response in patients, what has become colloquially known as the “cytokine storm”. [37–39] This has led to the successful use of interferons as part of the combination therapy for more severe patients. This also sparked investigations into leronlimab, which was shown to reduce the inflammatory response and plasma viral loads. Similarly, type I and III interferons restrict infection of cells. [40–42]
1 — https://go.nature.com/2ywsyws
7 — https://go.nature.com/2LUquBt
17 — https://go.nature.com/2LXbYZL
