Covid-19: Nphet paper envisages change to ‘more normal’ testing system

From the very early days of the pandemic, Ireland’s experience of Covid-19 has gone hand-in-hand with testing.

Concerns over whether we could test quickly enough and at sufficient scale dominated; backlogs of tens of thousands of samples accumulated. Flights carrying swabs to Germany, frantic hunts for reagent and rows over speed punctuated the news agenda.

As the virus took hold, testing played a key role in targeting measures designed to “flatten the curve” in the hope that slowing transmission could help the most vulnerable. The HSE built a sprawling and expensive infrastructure for testing, and its outputs – the daily case numbers, and the policy decisions they drove – have defined day-to-day life since. It was unprecedented, and is nothing like the normal systems for testing for a disease.

However, an unpublished paper drawn up for the National Public Health Emergency Team (Nphet) outlines how widespread testing could be radically scaled back as harm associated with infection reduces.

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"This unprecedented scale of testing to identify cases with mild symptoms and no symptoms was developed in the context of an overall public health response designed to interrupt transmission of infection to the greatest extent possible (test and trace)," writes Prof Martin Cormican, the author of the paper and the HSE's top infection control expert.

Rethink

The reduction in harm brought about by vaccines has now prompted a rethink, he writes. “The success of the vaccination programme requires a fundamental re-evaluation of the approach to testing for Sars-CoV-2 and how it links to the evolving public health response.”

Vaccines have reduced the worst outcomes, without eradicating the virus. The virus “is likely to remain globally endemic in the human population, although the reduction in harm is likely to increase and to be sustained in the context of acquired immunity”.

“In this context,” Cormican writes, “we need to begin to consider how we plan to transition towards placing testing... back in the framework within which we test for other infections.” In short, this means doing so “much more selectively”.

It envisages a seven-step path to a “more normal” testing system, beginning with not testing vaccinated and asymptomatic people, and moving on to discouraging testing of children under 13 with mild symptoms.

Then, vaccinated people with mild symptoms would stop under the plan, followed by asymptomatic and unvaccinated people. After this, testing of all people with mild symptoms would be excluded. Testing would be restricted to when it was requested by a doctor, and as part of “sentinel” surveillance systems to spot approaching waves of disease. There are multiple exceptions, and public health experts believe testing will remain part of daily life for the foreseeable future. But what the paper outlines is a step-change.

Social consequences

Testing, Cormican writes, is not without its own costs. “Medicalising daily life” has social consequences, and risks delaying access to healthcare for those with asymptomatic infection or residual traces of virus in their systems. It “undermines” years of work on self-care of respiratory infections, while the social and economic impact of a positive, asymptomatic test “may undermine confidence in the benefits of vaccination in preventing the disease”. Swabbing is uncomfortable, inconvenient, and has associated social and financial costs. Meanwhile, a focus on Covid-19 “that is disproportionate to its clinical and public health impact can result in diagnostic tunnel vision/confirmatory bias”.

The paper also points out that neither is scaled-back testing without risks, most importantly the potential to miss resurgent infection, the spread of variants, or outbreaks among vulnerable people infected by the asymptomatic.