Cambridge study reveals the shocking number of hospital staff that have COVID-19

Several studies published in the last few weeks have identified the various ways in which social distancing can be made more effective in the U.S. Chief among these is contact tracing.  

The principal objective of pandemic surveillance is identifying as many individuals as possible who have come into contact with an infected person and or object. This task is doubly important for communities that have endured disproportionate fatalities and hospitalizations compared to the rest of the world.

The UK  belongs to a small set of nations that have evidenced a usually high number of critical cases. Even with countermeasures initiated on a global scale,  this case disparity remains consistent. 

With cluster transmissions decreasing as a result of social distancing, researchers look to the essential cohorts that have been directed to continue operations during the COVID-19 pandemic. 

New findings motioned by Cambridge University might have located the most vulnerable sector. More discreetly, roughly 3% of healthcare workers continue to treat patients while unwittingly carrying the SARS-CoV-2 virus.

“Significant differences exist in the availability of healthcare worker (HCW) SARS-CoV-2 testing between countries, and existing programs focus on screening symptomatic rather than asymptomatic staff,” the authors write in the journal eLife. Over a three-week period (April 2020), 1,032 asymptomatic HCWs were screened for SARS-CoV-2 in a large UK teaching hospital. Symptomatic staff and symptomatic household contacts were additionally tested. Our data demonstrate the utility of comprehensive screening of HCWs with minimal or no symptoms. This approach will be critical for protecting patients and hospital staff.”

Screening of healthcare workers for SARS-CoV-2 and  the role of asymptomatic carriage in COVID-19 transmission

The new paper was informed by the test results obtained from the 1,032 otherwise healthy National Health Service staff members at Addenbrooke’s Hospital, located in Cambridge, England.

Even though these workers were deemed “fit for duty” just before the start of the study,  3% of the study pool tested positive for the novel coronavirus. Because testing resources are so limited, essential HCWs are only administered antibody tests if they display symptoms characterized as instructive by The Centers for Disease and Prevention. 

These include the following:

  • Fever
  • Cough
  • Shortness of breath or difficulty breathing
  • Chills
  • Repeated shaking with chills
  • Muscle pain
  • Headache
  • Sore throat
  • New loss of taste or smell
  • Persistent pain or pressure in the chest 
  • New confusion or inability to arouse 

Previously conducted research has suggested an unknown segment of the population remains asymptomatic for the entire duration of SARS-CoV-2 infection. In some cases, the adaptive immune response overreacts and weakens viral systems within a host. Other times, biological processes work so pristinely carriage does not beget overt signs of illness. 

In this study specifically, roughly 20% of the 3% who tested positive for the coronavirus didn’t feel any symptoms at all, 40% experienced very mild symptoms that did not hinder their ability to work, and the remaining said that they had felt a couple of the symptoms associated with COVID-19  but they cleared away in about a week’s time. 

All in all, a staggering 15,000 medical workers were routinely interacting with patients while infected by the coronavirus. 

Real-Time Quantitative Reverse Transcription was employed to detect viral RNA from a throat and nose self-swab in instances where participants were either asymptomatic or pauci-symptomatic (showing only a few symptoms compatible with a disease).  Clusters of HCW infection were discovered on two independent wards.

Most swab tests detect both living and dead viral material, though it is not known how long carriers remain contagious. It is assumed that carriers shed the most viral debris before the onset of symptoms but more research needs to be done to unpack the mechanisms behind this.

“Test! Test! Test! And then test some more,” proclaims senior author Dr. Mike Weekes, of the Cambridge Institute of Therapeutic Immunology and Infectious Disease, in a release. “All staff need to get tested regularly for COVID-19, regardless of whether they have any sort of symptoms – this will be vital to stop the infection spreading within the hospital setting.”

Habitual testing attends every level of pandemic relief. Without a clear understanding of the aggravators preventing COVID-19 suppression, transmission rates are doomed to outpace recovery.  

CW Headley is a reporter for the Ladders and can be reached at