The SARS-CoV-2 transmission riddle - Part 14 close contact
Of transmission and censorship
This was probably the most challenging riddle to write so far. The reason is simple: everyone knows what close contact means, but there are no universal definitions.
Is it a mode of transmission, or is closeness a variable? Does it involve touching someone, or can it include airborne particles emitted from a short distance? If so, what distance: 1, 2, 3 metres or more? And what particles do we include, droplets, aerosols, or fomites agitated by someone close to you?
You expect the international literature to be clear on these points and have universally accepted definitions. Not so.
When we reviewed international literature apart from the now well-known evidence quality problems, we came up against the problem of precisely what is meant by close contact. For example, the US CDC defines it as:
Close contact: Someone who was within 6 feet of an infected person for a cumulative total of 15 minutes or more over a 24-hour period starting from 2 days before illness onset (or, for asymptomatic patients, 2 days prior to a positive test result) until the time the patient is isolated.
The World Health Organization (WHO) includes direct physical contact with a probable or confirmed case, direct care for a patient with probable or confirmed COVID-19 disease without using proper personal protective equipment (PPE), and other situations as indicated by local risk assessments.
In our review, one hundred and one studies (39 per cent) reported definitions of close contacts, which were heterogeneous. But contact duration was unclear or not reported in over 90 per cent of the studies.
The few studies that undertook viral cultures in our review of close contact found replication-competent virus in 3/4 attempts, and attack rates seemed higher in close gatherings of people. So the evidence (despite its limits) points to distance (if that is what we mean by close contact) having a role in transmission, which is more significant in indoor settings.
The review process was interesting, as were the peer review and other comments we received. The content and tone ranged from supportive and positive to negative, calling into question our competence to undertake the review and WHO’s credibility in awarding us funding. So for you serial riddlers, the question is no longer does close contact facilitate transmission, but why would such a topic generate such diverse and aggressive responses?
It is the negative or demeaning responses that are most interesting. The review in its third version is published in F1000, a web-based open peer-review journal which is as transparent as they get.
You submit a paper, and it is formatted, checked for things like libel or bad language and then put online. No anonymity is allowed - something which gets our full support. Sometimes the authors are asked to suggest and approve a peer reviewer. Only some have an idea of what they will get.
At first glance, this is a good process, transparent, quick and with a format pleasing to the eye.
However, as we have discussed in the censorship and peer review posts, what should be a collaborative and scholarly process can become an unpleasant experience in which peer reviewers use their status to try to block publication.
This intent becomes evident when considering the content of their comments and their tone.
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