Hep C outbreak: Human error possible, but difficult to occur
Human error could have led to the hepatitis C outbreak in the Singapore General Hospital (SGH), said Dr Desmond Wai.
But here's the disclaimer: It is difficult for that to occur when the protocols in place are so well thought out, the gastroenterologist in private practice said.
On Tuesday, SGH revealed in a press conference that 22 patients in their renal ward had been infected with the hepatitis C virus (HCV).
Eight of the 22 have died. In four of those cases, hepatitis C is suspected to have contributed to the deaths, while three of the eight did not die of the disease.
The cause of one other fatality is still being investigated.
While the cause of the infections is still under investigation, initial findings point towards intravenous (IV) injectable agents as the source of the infection.
These are stored in multi-dose vials, which hold more than one dose of medication. SGH's chief nurse, Dr Tracy Ayre, said the vials can be shared between two or three patients.
With investigations ongoing, SGH reportedly said they cannot rule out any possibility, including foul play.
A similar hepatitis C outbreak also happened in Nevada, US, in 2007, with at least six patients infected.
Investigations found that when an infected patient needed another dose of the same drug from a multi-dose vial, a new needle was used, but with the same syringe.
A tiny backflow of blood from the first injection could have contaminated the syringe.
The HCV, now in the syringe, was then introduced into the vial of medicine, even though a new needle was used to draw more of the drug for other patients.
But Dr Wai stressed that a set of needle and syringe had to be disposed once it has any human contact.
"I can speak for only Mount Elizabeth Novena Hospital, where I work, but I believe many hospitals here follow similar levels of protocol," he said.
CONTAMINATION RISK
Some have questioned why multi-dose vials were used if they pose a risk of contamination.
Using insulin vials as an example, Dr Wai explained: "One bottle contains 100 units. At each time, a patient may require five to 20 units of insulin (before their meals).
"There's no way that the insulin can come in different units. Otherwise, the hospital will end up storing a lot (of vials). It is more economical to keep all the insulin in one bottle."
Precautions are taken at Mount E Novena Hospital to minimise the risk of infection, he said.
For instance, while multi-dose vials can be shared among a few patients, those at Mount E Novena use the same vial of drug throughout their stay.
But Dr Wai believes that the protocol in many Singapore's public hospitals, like SGH and the National University Hospital, should be similarly robust to Mount E Novena's as they are all accredited by the Joint Commission International (JCI).
JCI looks at certain standards, such as having a minimum distance between beds, and is considered the gold standard in global health care.
"All processes are scrutinised by external organisations like JCI, so they have to be very robust and foolproof.
"If the source (of infection at SGH) is indeed the multi-dose vials, then I would like to find out how it could have happened," Dr Wai said.
One bottle contains 100 units. At each time, a patient may require five to 20 units of insulin (before their meals). There's no way that the insulin can come in different units.
- Dr Desmond Wai, explaining why multi-dose vials are used
Steps to prevent contamination
Multi-dose vials were named one of the possible causes of the hepatitis C infections in the Singapore General Hospital. Gastroenterologist Dr Desmond Wai shows the precautions taken at Mount Elizabeth Novena Hospital to prevent the spread of infections with these multi-dose vials.
1 Each time a new multi-dose vial is used, the date and time the vial is opened will be written on its label.
At Mount Elizabeth Novena, patients do not share the multi-dose vials. Two nurses administering the medicine will first check two identifiers of the patient, usually their name and identification number or birthday. This prevents a mix-up of patients, Dr Wai explains.
After confirming the patient's identity and the dosage to be given, one of the nurses cleans the rubber cover of the multi-dose vial with an alcohol swab to remove any germs present.
2 The nurse then unwraps a disposable needle and syringe set from its plastic packaging. Each needle and syringe set is separately packed so they are kept sterile.
3 The required dosage is drawn from the vial. Sometimes, the nurse flicks the syringe to remove any air bubbles.
4 The nurse disinfects the site of injection with an alcohol swab, before giving the jab.
5 Immediately after the injection, the needle and syringe is disposed into a biohazard sharps bin - a small bin with a valve on top to prevent the needles from sliding out. Needles and syringes have to be discarded after the first human contact.
6 Other biohazard waste like used gloves are thrown in a biohazard waste bin. The vial is then kept away for the next use. After the patient is discharged, the opened multi-dose vial is given to the patient, or thrown away, even if the medicine is not used up. This is to prevent an infection from spreading, in the event that the vial has been contaminated.
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