Coronavirus Research Tracking - 16 October
Surface survival, reinfections, beliefs and behaviours
In this week’s Research Tracker there is a loose theme of susceptibilities. We look at two papers that made the headlines this week, and other articles on boosting older peoples’ immune systems, the influence of beliefs on behaviours, and ongoing experiments to determine if there is a more infectious viral strain.
The Research Tracker is prepared by Dr Robert Hickson for the Science Media Centre.
Viral survival on surfaces
A paper published in Virology Journal reports that infectious viral particles can, under certain circumstances, survive for 28 days on some non-porous surfaces (like glass, steel, & bank notes) at 20 degrees C. However, there are important qualifiers with the study. The tests did not mimic normal environmental conditions. They were done at constant temperatures and 50% relative humidity, and in the dark to avoid virus degradation.
Even under these conditions there was a 90% reduction in viral levels by seven days at 20 degrees. The relative risk of infection from surfaces compared with airborne droplets and aerosols is, therefore, likely to low. Still, frequent hand-washing and face mask wearing remain good protective public health practices where there are (suspected) outbreaks.
Fifth confirmed reinfection
Reinfection of a Nevada man about 48 days after a previous infection was confirmed by genomic sequencing. The results, published in The Lancet Infectious Diseases, is the fifth confirmed reinfection, and the second where the subsequent infection resulted in more severe symptoms. Why the second infection was more severe is unknown. There are several possible explanations but insufficient clinical information.
An accompanying comment on the paper notes that detection of reinfections is biased towards those displaying symptoms, so the frequency of SARS-CoV-2 reinfection is unknown.
A perspective published in Science in response to the paper considers whether SARS-CoV-2 will become endemic (that is, persist like other human coronaviruses). It notes that there is still considerable uncertainty about this.
If it did become endemic, and effective treatments were not widely used, the authors suggest that overlapping infection cycles between Covid-19 and influenza may pose a serious threat to public health systems.
Giving elderly people “anti-aging” drugs may help with vaccinations
A news feature in Nature discusses the possibility that giving the elderly “anti-aging” drugs may stimulate their immune system, and so act as a booster for Covid-19 vaccinations. Data on the immunity boosting potential of some of these drugs, gathered before the pandemic, is encouraging but not yet convincing.
How vaccines work
A history and discussion of why and how vaccines work is published in Cell.
Susceptibility to misinformation
National surveys in five countries were used to assess predictors of belief in misinformation about Covid-19. The UK, Ireland, Spain, Mexico and the USA were surveyed. The results, published in Royal Society Open Science, indicate that the majority do not believe such misinformation.
There were, though, reasonably large groups (one fifth to a third of respondents) in each country that believed at least one piece of misinformation. Those who trusted the misinformation were generally less likely to comply with public health guidance, but this varied between countries.
These results support some previous research. However, the relatively small sample sizes, inter-country variability, and self-selection and self-reporting biases can make it difficult to generalise the findings.
Beliefs and attitudes correlate with behaviours
A paper in BMJ Global Health, that is also probably not too surprising, reports that in the US those who trust Fox News more are less likely than CNN viewers to perform Covid-19-related preventative measures. The paper’s authors emphasise that it shows correlation, not causation.
The results of two Polish surveys, published in PLoS One, found that those who held right wing authoritarian views were more likely to support surveillance technologies during the pandemic, compared with those holding less authoritarian views.
Still not clear if there is a more infectious strain
For several months there has been discussion over whether a variant of the virus with the amino acid glycine at position 614 (called “614G”) in the spike protein is more infectious than the original strain with aspartic acid (“614D”). As noted in an earlier Highlights, this remains unresolved, illustrating the complexities of transmission dynamics and the challenges of studying it in laboratories.
A key step for SARS-CoV-2 to infect cells is cleaving part of the spike protein off the virus. A laboratory study, as yet not peer reviewed, found that the 614G variant was easier to cleave than the 614D protein.
This is suggestive that the 614G variant may be more infectious. However, the experiments did not use whole viruses, and cell infection was not assessed.
Another study, also not yet published, reports that the 614G variant can reproduce more efficiently than 614D in one type of cultured human airway epithelial cell. However, it did not show this advantage in cells from the lower respiratory tract, and the 614G variant was more susceptible to neutralising antibodies.
The same study reports that infection of small numbers of mice and Syrian hamsters with the two viral types resulted in similar viral loads and lung damage. The 614G virus did though spread more quickly from infected to uninfected hamster neighbours.
Interpreting these studies requires caution. Laboratory-based infection studies often do not accurately reflect natural infection and transmission.