A third of midwives with COVID-19 ‘asymptomatic’ 

13 August 2020

A third of maternity care workers who contracted coronavirus may have experienced no discernible symptoms, a study by UK researchers suggests.

Their research found that one in six maternity health workers they tested had been infected with Covid-19, of whom one in three were completely asymptomatic, the Nursing Times reports.

Worryingly, the researchers said that 58% of those who tested positive never met the government's criteria for self-isolation, and, therefore, did not self-isolate and continued to work as normal in their hospital.

Their study follows an earlier study suggesting that over 40% of people infected with coronavirus may display no symptoms.

The new research was based on findings from two London hospital maternity units and has now been published in the journal Anaesthesia.

The authors of the study noted that it was thought that Covid-19 caused a milder illness in pregnancy with a greater proportion of asymptomatic carriers.

This, they said, had important implications for the risk of patient-to-staff, staff-to-staff and staff-to-patient transmission among health professionals working in maternity wards, reports the Nursing Times.

Researchers set out to investigate previously undiagnosed coronavirus infection in staff at two maternity units – one at University College London Hospital and the other at St George's Hospital.

The study included 40 anaesthetists, 108 midwives and 52 obstetricians with no previously confirmed diagnosis, who were tested for prior Covid-19 infection using antibody tests.

A total of 14.5% tested positive, with the highest positivity rate found in midwives, followed by obstetricians and then anaesthetists.

Of those who tested positive for Covid-19 antibodies, 35.5% were completely asymptomatic. Fever or cough were only present in 20.7% and 34.5%, respectively.

Anosmia – loss of sense of taste and smell – was the most common symptom occurring in 51.7% of seropositive participants.

More than half of those who tested positive had not met the national criteria for self-isolation at any point, so did not self-isolate and continued to provide patient care in the hospital setting.

The authors said the prevalence of Covid-19 in the London hospital units was similar to estimates in the general population in Greater London at 14.5%, based on sampling from blood donors.

They suggested that obstetric staff appeared to have a lower risk of occupational viral transmission because pregnant women may be less infective than respiratory or acute emergency patients.

The authors said: “Our study suggests that extreme caution is advisable in maternity settings, particularly the consistent use of effective personal protective equipment (PPE) and other known effective measures including social distancing of staff and the regular washing of hands.

“We also recommend that all obstetric healthcare institutions should consider regular serology testing for staff, as well as the immediate isolation of any staff who lose their sense of taste and smell, even in the absence of cough or fever.”