We should change the testing process to require that everyone who gets a negative test comes back for a repeat test within a week, says Dr Parmjeet Parmar.

People who were recently notified they had been at ‘places of interest’ in Auckland queued up outside testing stations desperate to get a test. The results of these tests meant a lot to these people and the country as a whole. 

It is important that the trust people have in the so-called ‘gold standard’ PCR test is maintained.

But we have seen cases that tested negative more than once before later testing positive, and some have been identified only because they developed symptoms.  

Even more intriguing is that the most recent current cluster and the previous August 2020 cluster both still have missing links – we still don’t know how these clusters started.

We know that Coronavirus can transfer through surfaces but the most likely mode of transmission is airborne – humans to humans.

It is possible that those ‘missing links’  – the people that infected the first case identified – remained asymptomatic, or developed only mild symptoms that they dismissed as general fatigue. Or perhaps they got tested but their test result was negative – a false negative – and they went back to their normal life.

The message from the August cluster and the February cluster is loud and clear. If we are still serious about the elimination strategy for Covid-19 we need to get serious about these missing links.

Lockdowns are just one way that will help temporarily break the chain of transmission, as we have seen in our own experience. We need more ways rather than just imposing another lockdown. We need long-term strategies to ensure the security of our communities without costing the country hundreds of millions of dollars.

There are some obvious fixes that can be implemented instantly. The ‘gold standard’ test can deliver ‘gold standard’ results only if we have ‘gold standard’ processes and procedures while conducting the test.

In countries like the UK or the US, with high infection rates, the question of false negatives is easier to dismiss as a minor issue or an acceptable risk. But that is not the case for us.

Given the small number of positive cases in our community, what matters for us is not the number of negative test results reported each day but the chances of any of those being a false negative.

Because that one false negative could be responsible for creating a whole new cluster, and a new lockdown.

Auckland has already sacrificed so much. It is time the issue of false negatives is dealt with to the extent it can be. 

Firstly, we need to minimise the risk of false negatives arising because of when individuals are tested (as viral loads fluctuate across the infection cycle). Secondly, it is time that the public demands the highest level of assurance from the Government and the Ministry of Health that the sample collection is done in a way that leaves no chance of it becoming a false negative.  

The issue of the fluctuating viral loads potentially leading to false negatives can be dealt with by changing the testing process to require that everyone who gets a negative test comes back for a repeat test within a week.

At the end of the day people are willing to spend so much time in testing queues because they have a reason to come forward to get tested.  They would want to know for sure that they were Covid-19 free when they were tested.

In our unique circumstances of such low levels of cases in the community, for community testing we cannot compromise accuracy for speed. Our infections are not like the UK that needs speed first with accuracy to follow.   

We cannot afford delayed detections or undetected cases, as it is those undetected or delayed ones that will form the next cluster- and again form a link that will remain missing.

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