30 May 2022

Covid-19 reinfections not being tracked in NZ as examples tipped to rise

6:53 pm on 30 May 2022

Esmé Putt is back in bed with Covid-19 for the second time. After testing positive in April and returning negative results in between, she got the two lines again last week.

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A positive rapid antigen test. Photo: Unsplash / Annie Spratt

While her symptoms have been milder, she's still not feeling great - one thing, however, has stayed the same: "being really really really tired".

"If I get a burst of energy back, and then I'll try do something like watch a movie and about halfway through that I'll just feel tanked."

Getting Covid-19 twice, especially within a 90-day window is rare, but it can happen.

It can also be the case that someone who got Covid-19 once returns a false positive second test and perhaps has the flu instead.

That's what makes an official count difficult.

Despite Putt recording both her positive results online, the Ministry of Health (MOH) has no way of collecting that crossover data.

University of Canterbury professor, Michael Plank

Professor Michael Plank Photo: Supplied.

University of Canterbury Professor Michael Plank estimated reinfections were low but would be on the rise.

"It's possible that we're not seeing many reinfections yet and that may be because people might not feel like they need to test if they've had Covid-19 before," Plank said.

"But it's quite possible that reinfections are a small fraction of the total number of cases at the moment - but it's likely that will change."

Research was underway to find out if reinfections resulted in mild, similar, or worse symptoms.

University of Otago Associate Dean (Pacific) and immunologist Dr Dianne Sika-Paotonu said initial findings showed that it depended on the variant of Covid-19.

A study from the UK has shown reinfections with the Alpha strain tended to be less severe when compared with the primary infection.

But people who were reinfected with Delta or Omicron were more likely to experience symptoms.

"However, ongoing work will be needed to understand more about whether reinfections for the Omicron, and all its subvariants, are more or less severe when compared to the primary infection," Dr Sika-Paotonu said.

GPs have been noticing more patients anxiously calling up with Covid-19 symptoms again.

Royal New Zealand College of General Practitioners medical director Dr Bryan Betty said it was tricky to get an accurate picture.

"There's no doubt that some people are definitively getting reinfected.

"One of the confusing features of the moment is that symptoms of Covid are very similar to symptoms of other viral illness - such as influenza - so sometimes it's a bit difficult to disentangle what is going on."

The MOH said people who started getting Covid-19 symptoms within the 90-day window of their first infection should not get re-tested because it could be inaccurate.

Instead, people who were sick again needed to stay home until they felt better.

Their household contacts still had to isolate again, unless they had Covid-19 in the last 90 days, or if they had isolated as a household contact within the last 10 days.

The MOH is currently working on its case-recording system so that it can formally collect reinfection numbers.

It may be a useful tool in the future, as Professor Plank said reinfections were something that would likely continue.

"There's no guarantee that the severity [of Covid-19 subvariants] will go down, but unfortunately I think it is the reality for many people that you will catch Covid multiple times over a long period of time - several decades."

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