Investigation into Covid-19 outbreak at Durban hospital reveals virus spread through patient to patient transfer
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Durban - An investigation into the Covid-19 outbreak at Durban's St. Augustine's Hospital has found the cluster outbreak was as a result of patient to patient transfer after both were admitted to the hospital around the same time.
The findings of the investigation, led by UKZN academics, Dr Richard Lessells, Professor Yunus Moosa and Professor Tulio de Oliveira found that between March 9 and April 30, there were 119 people – among them 39 patients and 80 staff members – who had confirmed cases identified at the hospital. Fifteen of the 39 patients died.
According to the report, the most plausible explanation for the outbreak is that there was a single introduction of the severe acute respiratory syndrome-related coronavirus 2 (SARS‐CoV‐2) to the hospital in early March, most likely through transmission from a patient being assessed for Covid-19 in the emergency department to another patient being admitted at the same time with a suspected stroke.
The virus then spread widely through the hospital, involving patients and healthcare workers in at least five different wards.
The investigation harnessed the genomics expertise of the KwaZulu-Natal Research Innovation & Sequencing Platform (KRISP), a UKZN research centre.
Lessells said genetic sequences of SARS-CoV-2 were generated and analysed to help understand the spread of the virus through the hospital.
"Investigation methods included medical record reviews, ward visits and interviews with health care workers and management. Through detailed analysis of the timelines – which wards patients were on, when their symptoms started, when they tested positive for SARS-CoV-2 – we were able to build a hypothesis of the most likely chain of events and understand how the virus spread around the hospital," he said.
Lessells said genetic analysis supported this hypothesis and gave the team the confidence that their explanation was correct.
"To us, our findings highlighted how easily and quickly this virus can spread through a hospital. The initial spread of the virus was not recognised at the time, because the first patient who we think was infected in the emergency department was not initially suspected of having Covid-19. She did not have any of the typical risk factors and initially only had fever without cough or other respiratory symptoms. By the time she was diagnosed with Covid-19 and the hospital began responding to the outbreak, several other patients and healthcare workers had already been infected," he said.
Lessells said investigations into the outbreak at the hospital began on April 4, after the identification of 13 confirmed cases and three deaths at the hospital.
According to De Oliveira, the investigation also revealed the outbreak at St. Augustine’s Hospital led to clusters of Covid-19 cases in a local nursing home and in an outpatient dialysis unit operated by National Renal Care on the hospital campus.
“Overall, we estimate that the hospital outbreak and its spread to these other institutions accounted for about 14% of Covid-19 cases in KwaZulu‐Natal reported up to 30 April," he said.
De Oliveira said this highlighted the risk that outbreaks like this became what medical experts called "amplifiers" of transmission, meaning they fuelled transmission in the wider community.
He said that although the case fatality rate was high, almost all the deaths were associated with the recognised risk factors such as older age and chronic health conditions such as diabetes, hypertension, heart disease and kidney disease.
"The hospital performed systematic testing of all staff members as part of their response to the outbreak. The 80 staff cases represent approximately 5% of all staff members tested for SARS‐CoV‐2. Fourteen staff members required hospital admission but none were admitted to intensive care and none died," he said.
He added that although the majority were nurses or nursing students, there were a few cases in staff not involved in direct patient care.
"Whilst the investigation cannot rule out that some of these infections were acquired in the community, the phylogenetic analysis showed that all 18 DNA sequences from the outbreak were almost identical, pointing to a single source of infection and widespread transmission in the hospital," he said.
Professor Moosa said that many of the core recommendations to reduce the risk of similar outbreaks came back to the strengthening of infection prevention and control (IPC) systems and practices throughout hospitals,
“We call on management to promote a culture in which IPC is everyone’s responsibility and that everyone has a role to play," he said.
Specific recommendations include:
• Hospitals need to establish separate zones (and separate entry points) for people who have confirmed Covid-19 (red zone), people who might have Covid‐19 (yellow zone), and people who are unlikely to have Covid‐19 (green zone).
• Vigilance throughout hospitals for acute respiratory illness, especially in green zones where patients considered low risk for Covid‐19 have been admitted.
• Limiting the non-essential movement of patients between and within wards and limiting the movement of staff between different wards.
• Training on Covid‐19, especially on infection prevention and control, should be mandatory for all staff and implementation of IPC practices should be monitored closely.
• The importance of hand hygiene needs to be continually emphasised and
hand hygiene practices need to be monitored.
• Environmental cleaning practices need to be aligned with the national Covid‐19 IPC guidelines and the national IPC framework manual.
• Physical distancing inside and outside the hospital should be promoted.
• Consideration should be given to weekly PCR testing of all frontline staff.
The report has been shared with the University of KwaZulu-Natal executive management team; the KwaZulu-Natal Department of Health, the Chair of the Ministerial Advisory Committee on Covid-19, Professor Salim Abdool Karim, Netcare management and National Renal Care management. Feedback sessions have been run at St. Augustine’s Hospital with hospital managers, unit managers and doctors and the findings have also been presented to the Ministerial Advisory Committee and the National Institute for Communicable Diseases (NICD). The report is also being made public today, together with the data generated and analysed.
Professor Lessells said the Covid‐19 pandemic was an unprecedented challenge for the health system and the community in South Africa.
“We hope that lessons learnt from this nosocomial outbreak can be used to highlight areas that can be strengthened across the private and public health system, so as to prevent nosocomial outbreaks becoming a major amplifier of Covid‐19 transmission," he said.
Both St. Augustine's and Kingsway hospitals, which fall under the Netcare group, were closed following the outbreak. After undergoing extensive cleaning and sanitisation, both hospitals were re-opened on Monday, May 11.