September 24, 2020

expert reaction to unpublished conference abstract on symptoms and antibodies in key workers who thought they’d had COVID-19

A conference abstract, press released from the European Society of Clinical Microbiology and Infectious Diseases Conference on Coronavirus Disease (ECCVID), discusses symptoms and antibodies in key workers who thought they’d had COVID-19.

Prof Paul Hunter, Professor in Medicine, UEA, said:

“The study by Ranya Mulchandan on self-reported symptoms and whether these can be confirmed by antibody (Ab) tests is an important and well conducted study.  One of the concerns in any antibody study of COVID-19 is how long antibody tests remain positive after an infection.  The authors were able to estimate the impact that Ab decline would have on their results and were able to conclude that during the time scale of the study an Ab decline would not materially affect their conclusions.  Consequently the results presented are likely to give a good estimate of the proportion of episodes that individuals believe to be COVID-19 are or are not in fact due to COVID-19.

“The main conclusion is that about only half of health care workers (HCW) who believe they have had COVID-19 based only on the presence of symptoms had not in fact had the infection.  For the other emergency services this was even lower with just 28% of people who believed they had the infection being positive.

“Also of note was that 10% of HCW and 5% of other emergency worker who had had no symptoms were positive probable indicating that that had a asymptomatic infection.

“One of the unresolved debates is whether COVID-19 was spreading in the UK much earlier than official statistics would suggest.  There are many people who believe that they had an infection very early in the year.  The World Health Organization classification would call these Early-probable infections.  The positivity rate in emergency workers (4%) who fitted into this case definition was the same as for people with no symptoms.  For HCW the rate was a little higher 16%.  The results of this study would suggest that the vast majority of people who believe thy had had COVID-19 in the first couple of months of this year but had not had a confirmed test at the time had not in fact had the infection then or subsequently, even if now antibody positive.

“So in conclusion the majority of people who believe that they have had a COVID-19 infection but have not had a positive swab or Ab test will not in fact had actually been infected.  This is important because if someone believes themselves to have been infected and no longer takes steps to protect themselves then many will be putting themselves at risk.”

The abstract ‘Signs and symptoms of COVID-19 associated with antibody detection: cross sectional study in UK key workers’ by R. Mulchandani et al. has been press released from the European Society of Clinical Microbiology and Infectious Diseases Conference on Coronavirus Disease (ECCVID). 

There is no paper and this is not peer-reviewed.

Declared interests

None received.