Samba 11- a ready-made solution to meet Zim’s testing target A lab scientists carrying some tests using a Samba point of care machine

Paidamoyo Chipunza, Senior Reporter

In April, Government set an ambitious target to test at least 1,000 people for Coronavirus (COVID-19) a day.

Testing criteria was subsequently widened to include all people with one or more signs and symptoms of COVID-19 despite history of travel and all patients above 60 years of age in hospital admission who might have chronic illnesses that include asthma, diabetes, high blood pressure and heart disease. All those who were working during the 21-day national lockdown and all returnees also fall into this widened category of COVID-19 testing candidates.

Zimbabwe, just like many other African countries, is in the process of opening up its economy and society while adjusting to the new normal. This process includes re-opening of the tourism sector, restaurants, and schools, which will naturally increase the number of people requiring testing.

Suppressing transmission of the virus is one of the five priorities recommended by the World Health Organisation (WHO) if countries are to curb resurgence of cases as they open up their economies and societies. Addressing journalists during a virtual meeting recently, WHO director general Dr Tedros Ghebreyesus said testing, contact tracing and quarantine were key to suppressing transmission of COVID-19.

“Whether countries have no cases, clusters of cases or community transmission, there are steps all countries can take to suppress the spread of the virus,” said Dr Ghebreyesus. He emphasised the importance of finding cases (through testing), tracing and quarantining exposed individuals saying this was the ‘single most important intervention for breaking chains of transmission.’ In his recommendations, Dr Ghebreyesus said early identification of the cases was critical in suppressing transmission.

Although Zimbabwe set a target to test 1,000 people a day since April, just over 34 000 people have so far been tested.

About 47,000 others were screened using the rapid antibody-based test kits. However, these rapid test kits cannot be used for definitive diagnostic as they only indicate past infection. They also lack accuracy. In fact, their sensitivity varies from 34 to 80 percent. Sensitivity refers to the ability to correctly identify positive cases. Therefore, using these tests may end up creating more issues with false negative results. According to WHO, half or more of COVID-19 infected patients could be missed by such tests depending on the group of patients tested. Therefore, WHO does not currently recommend the use of these rapid tests for patient care.

A laboratory expert from the Chinese anti-COVID-19 team which completed its visit to Zimbabwe last month, Dr Zhang Di said the country must enhance its screening and testing capacity through molecular amplification platforms such as PCR to effectively combat COVID-19.

Speaking after visiting a provincial laboratory at Chinhoyi district hospital, Beatrice Road Infectious Disease Hospital and National Reference Microbiology Laboratory in Harare, Dr Zhang said PCR testing was the gold standard in confirming COVID-19. “If we can directly use molecular amplification testing methods such as PCR, that would be good because it is the current gold standard, but of course we have to strike a balance between costs and available resources,” said Dr Zhang.

Zimbabwe has decentralised laboratory-based molecular amplification testing from the National Reference Microbiology Laboratory in Harare to Bulawayo.  Provincial and some selected district hospitals in the country are using the GeneXpert platform to test for COVID-19.  All this was part of measures to reach the target of testing 33,000 people per month. As mentioned earlier, the target has been elusive.

There remains a huge demand for molecular tests, as the available platforms are battling growing backlogs of samples, with testing only available for selected groups and individuals.  However, meeting this demand is important in getting an accurate picture of the disease prevalence in the country.

In an interview with The Herald recently, Mashonaland West acting provincial medical director Dr Gift Masoja said while the province has started PCR testing, most districts in the province did not have functional machines. He said this was forcing them to continue sending samples requiring PCR to Harare, and it takes many days before results are returned. The province was also experiencing a shortage of swabs and transport media used to collect samples for testing from suspected cases. He said this has seen the province accruing a huge backlog of people supposed to undergo the tests, particularly returnees in quarantine facilities.

But the province, just like many in the country, has other molecular platforms, such as the SAMBA II, which can be used to expand PCR testing and clear the swelling backlog.

This point of care technology gives results in 75 to 90 minutes and recently got approval from the Public Health England for COVID-19 following independent assessments. It’s ability to correctly identify positive cases (sensitivity) was 98.7 percent while its ability to pick up negative cases (specificity) was 100 percent.

United Kingdom, one of the countries where COVID-19 has affected most, has since deployed the SAMBA Corona test in 21 National Health hospitals. The test has been developed by Diagnostics for the Real World (DRW) – a spin-off company from the Cambridge University. In a study conducted independently in Cambridge with 149 patients, SAMBA II was associated with faster time to triage from the emergency departments, release of isolation rooms, avoidance of hospital bay closures, and allowed discharge to care homes and faster access to hospital investigations and procedures.

Zimbabwe currently has the widest coverage of SAMBA-II point of care machines with about 125 machines stationed at 25 district hospitals across all provinces. The SAMBA II technology detects tiny traces of genetic material belonging to the virus and amplifies it billions of times chemically. A nasal and throat swab is collected from a patient and uploaded to the machine, which runs the fully automated process. The machine can be placed literally anywhere and operated by anyone with minimum training.

Dr Masoja said, “If we deploy the SAMBA II as well, that would be good because they will complement technologies already on the ground. Judging from our testing backlog, we surely need more platforms, more cartridges and most importantly swabs and transport media to collect samples from suspected cases”.

With 125 machines, Zimbabwe could conduct an additional 1000 PCR tests a day.

The African Union through the Centre for Disease Control also embarked on a massive testing campaign through the Partnership to Accelerate Covid 19 Testing (PACT) initiative.

Officially launching the initiative recently, Africa CDC director Dr John Nkengasong said testing was the only winning formula at the moment to combating COVID-19 in the absence of a vaccine.

“In the absence of a vaccine or cure, there is only one formula to fight COVID-19 and that formula is the Partnership to Accelerate COVID-19 Testing (PACT) initiative, which is the ability to test, trace and isolate those positive. That is the only winning formula to COVID-19,” he said.

He said with more partnerships, the continent was looking forward to test between 10 and 15 million people of COVID-19 in the coming weeks. He also implored on countries to improve the turnaround time of results for suspected cases.

Chief coordinator to the national response to COVID-19 in the Office of the President Dr Agnes Mahomva said Government was looking at platforms that can produce results quickly.

She said these platforms were instrumental at ports of entry particularly Beitbridge, which is usually characterised by huge inflow of returnees.

“We do not want people to crowd and spend time at our ports of entry as they await testing and release of results, so we are considering purchasing of platforms that can produce results quickly,” said Dr Mahomva.

She said work was already in progress to purchase this equipment.  Asked on the use of technologies such as SAMBA II point of care machines which are already installed in 25 sites in the country, Dr Mahomva said use of the technology would be guided by the laboratory department. She said at the moment, the main challenge to scaling up testing to desired levels was with consumables and cartridges. In this respect, providing additional Corona testing with SAMBA machines would overcome the supply issues of current platforms.

 

You Might Also Like

Comments

Take our Survey

We value your opinion! Take a moment to complete our survey