On Nov. 23, AstraZeneca published a report of results from an interim analysis of clinical trials of their vaccine candidate. Instead of conducting one large phase-3 trial, these results pooled in data from two separate trials conducted in the UK and Brazil with a trial error that resulted in different dosing regimens for each trial. In the UK trial, candidates were given one half dose and one full dose at least a month apart, whereas in the Brazil trial, candidates were given two full doses at least a month apart. It was observed, however, that there was a large variation between the efficacy of the half/full regimen (90%) and that of the full/full regimen (62%). This puzzled the AstraZeneca and Oxford researchers over why there appeared to be greater protection afforded by a smaller dose.

Adding to doubts about the data, the report stated that data from 23,000 participants was assessed and 131 positive Covid-19 cases were observed, but there was no breakdown offered for the number of participants in each separate regimen and the number of placebos that were administered. The dosing error casts doubt on overall results, and statisticians would have to rely on subgroup analysis which could potentially be inconclusive due to a small sample size. AstraZeneca maintains that their results are statistically significant but are yet to release detailed numbers. This could be a potential setback for a vaccine candidate that claimed to be cheaper than a cup of coffee.

An article that appeared in New York Times on Nov. 18 argued that while deep-cleaning practices and surface-scrubbing can be effective in generating a sense of security against Covid-19, there is “little to no evidence that contaminated surfaces can spread the virus.”

Dr. Kevin P. Fennelly, a respiratory infection specialist at the U.S. National Institutes of Health, said, “In my opinion, a lot of time, energy and money is being wasted on surface disinfection and, more importantly, diverting attention and resources away from preventing airborne transmission.” While hand-washing and sanitizing practices play an important role in mitigating the threat of the virus, experts encourage more focus on improving ventilation systems as there is a growing body of evidence that points to airborne transmission.

However, Gabrielle String, a postdoctoral scholar at Tufts University, emphasized that it is too early to have any conclusive results on whether surface transmission occurs. A study at Tufts that surveyed 96,000 articles noted that only 78 were on surface disinfection.

“We still have such a gap in understanding how surfaces contribute to the transmission of [Covid-19],” said String, adding, “Researchers need to standardize how we’re testing because we really need to compare data so that we can make solid recommendations.”

Given that temperature and humidity could affect how the virus survives on surfaces, it is wise to keep scrubbing while avoiding communal airspaces.