Update on SARS-CoV-2 Research (3)
An analysis of patients (n=4182) who recovered from COVID-19 in the UK shows that a relatively large proportion of patients showed persistent symptoms a long time after recovery. Of these patients, 13.3 % reported symptoms lasting more than 28 days, 4.5 % for longer than 8 weeks and 2.3 % for 12 weeks or longer. 
The SOLIDARITY trial run by the WHO in 30 countries has reported the results of the investigation of four treatments for COVID-19. Remdesivir, lopinavir/ritonavir, hydroxychloroquine and interferon-β1a (n=11266) were evaluated. None of these reduced mortality to a statistically significant extent, initiation of ventilation or hospitalisation duration (in unventilated patients or any other subgroup). 
A large international study has identified one important factor which can cause life-threatening COVID-19. The presence of antibodies against a protein of the immune system (interferons) is found in ~10 % of patients with critical COVID-19, but in no asymptomatic patients. This effect was seen more in men (12.5 %) than women (2.6%).
This finding has two important implications. First, patients with such antibodies must not be used for donation of convalescent plasma to others. Second, detection of these antibodies (regardless of age group) can be used to classify someone as high risk. 
Examination of the immune responses of patients in the US has revealed some insights as to what parts of adaptive immunity seem to be important in disease progression. The presence of neutralising antibodies seems to be less important than the presence of T-cells.
However, as expected, patients who exhibited neutralising antibodies, CD4+ and CD8+ T-cells seemed to have the best clinical outcomes. The number of naive CD8+ T-cells was also strongly correlated with disease severity. Notably, the number of naive T-cells is reduced with age. 
A separate examination of patients finds a similar but more complicated pattern. 
Economists in Switzerland have signed an open letter calling for a second lockdown in the country which is experiencing a rapid increase in both cases and deaths. They argue that the economic consequences of the pandemic at this point will be felt more if a lockdown is not put in place. [6,7]
An interesting excerpt reads:
“Exploiting these contrasting policies, Andersen et al. (2020b) estimate that aggregate spending dropped by around 25 percent in Sweden and, as a result of the shutdown, by an additional 4 percentage points in Denmark. Hence, the majority of the economic contraction is caused by the disease itself — regardless of mandatory social distancing laws. The cumulative death toll in Sweden, however, has to date been far greater than the one in Denmark (Our World in Data, 2020).”
The preprint referred to [Andersen et al. (2020b)]is also referenced here for convenience. 
An international collaboration has attempted to estimate the number of infections in countries around the world. To do so, they based their estimation on death numbers, age-stratified IFR and seroprevalence studies. Their findings are interesting and cannot be concisely summarised, so it is highly recommended to visit the source. 
Note: this is a much more sophisticated and refined, but similar approach to the question as was taken by the author of this blog in mid August. It is very encouraging to see this done properly and it is very interesting and informative.