Tag Archives: influenza

“Susceptibility to Influenza”

Confessions of a Microbiologist, , ,

If you live in the Northern Hemisphere you may have found that your laboratory was swamped by incoming influenza tests this season?

You would not be alone.

Influenza is an unpredictable beast. In my own neck of the woods, New Zealand, the 2015 season was busier than usual, the 2016 season was almost non-existent, and the 2017 season was very average.

Nobody knows what will happen with influenza during 2018.. (Note that as NZ is in the Southern Hemisphere, our winter is June, July , August, right in the middle of the year).

Often you will see Influenza “experts” on TV making predictions about how severe the forthcoming influenza season will be. However such predictions come with huge pinches of salt. You might well be better off predicting the stock market…

The truth is that we don’t really know how bad the forthcoming influenza season is going to be, whether you are an expert or just an interested bystander.

And as a result we have no idea how much each influenza season is going to cost a diagnostic laboratory that performs influenza testing.

Let’s say a bog standard Influenza/RSV PCR costs approximately $30. In a quiet season 1000 tests might get performed in a medium sized hospital. However in a busy season 5000 tests might be required, with an excess cost of $120000. This would of course cause the laboratory manager some sleepless nights!

I am glad I am not a laboratory manager..

And then there might be an influenza pandemic…

The same goes for Public Health Laboratories. The numbers of samples coming in for antigenic sub-typing will be closely related to the severity of the influenza season.

Contracts that laboratory providers have with healthcare funders need to take this unpredictability into account. Some sort of clause like “The diagnostic laboratory will perform up to X Influenza PCRs during the Influenza season. If this number is exceeded, further funding will be negotiated”. Unfortunately this is often not the case. Often laboratory providers will be so desperate to get the contract signed and sealed that they will accept these risks, and manage such problems reactively.

From a financial point of view, microbiology laboratories are very susceptible to influenza test volumes, just like they are susceptible to emerging diseases and MDROs, cohorts where “unexpected testing” may need to take place.

There will of course be some laboratories who are reimbursed per test performed (fee for service). Those places of course would be hoping for a pandemic every year!, but such laboratories/funding arrangements are getting less and less common. The funders are not daft!

I hope for a quiet influenza season this year, and that is nothing to do with my personal risk! (I look forward to receiving the quadrivalent vaccine in the next couple of months).

Michael

“Ward based PCR”

Future of Microbiology, , ,

There are a couple of new systems just on the market which I suspect will revolutionise PCR testing, particularly where an urgent result is desirable. This is often the case when trying to diagnose Influenza and RSV in the acute care setting.

Cepheid and Roche have both released benchtop PCR systems for Influenza and RSV testing which can be placed in the ward/ED environment, requires minimal training and can give you a highly sensitive result for influenza/RSV in well under an hour.

“Highly sensitive” are the key words here. This is in contrast to rapid antigen tests for Influenza and RSV which although can be useful in certain circumstances, are limited in their clinical usefulness by sub-standard sensitivity. RSV and Influenza rapid antigen tests are now living on borrowed time….

The other highlight is “under an hour”. This allows real-time management of the patient in the ED./acute assessment ward (including treatment, isolation, cohorting, discharge etc.) based on the result of the PCR test.

The big downsides of course are the cost and the “one at a time access”. More expensive (the cost will come down)than traditional batched PCRs it might be a while before such testing systems become commonplace. (A lot depends on the funding model of your healthcare system.)

But they will, you can be sure of that.

Michael

Influenza Pandemic: Plan or Panic

Confessions of a Microbiologist, ,

I have been keeping half an eye on the current situation with the H7N9 avian influenza strain currently infecting humans in Eastern China. For more details on this click here.

3D_Influenza_virus

The current Outbreak made me ask myself two questions:

  •  If the 1919-20 pandemic Influenza strain (Spanish Flu) emerged in today’s world, would it have the same devastating impact that it had back in 1919?
  •  Is there a chance we could have in the future a pandemic of equal (or greater) severity as the Spanish Flu?

My personal answers to these questions are No and Yes respectively.

The world has changed a lot since 1919. In 1919 there was massive displacement of population following WW1, there was great poverty and there were no antibiotics to deal with post influenza bacterial pneumonia. Nor was there any Influenza vaccines. For these reasons I don’t think the 1919 pandemic strain would have had nearly the same impact today.

But yes, I do think we could potentially have another pandemic as severe as 1919. It would just take a more pathogenic Influenza virus to do this, and we know that antigenic shift and mixing of Influenza strains from different species certainly have the potential of creating very pathogenic viruses. Fortunately most of these strains turn out to have low transmissability between humans.

We have had at least four recognised Influenza pandemics in the past century (Spanish Flu 1919-20, Asian Flu 1957-58, Hong Kong Flu 1968-69, Swine Flu 2009-10). The next one will not be a matter of “If”, but “When”. Fortunately the 2009 H1N1 Influenza pandemic, although very transmissable, was no more pathogenic than the usual seasonal strains.

None of us particularly enjoy putting in a lot of work to plan for something which may or may not happen during our working lifetimes. But this is what needs to happen. I am not saying it is easy either. To try and draft a policy to prepare for an Influenza pandemic of totally unpredictable size and severity is one of the hardest things I have had to do as a microbiologist. Some might say that drafting such a policy is close to impossible. But we need to try, in an attempt to at least reduce the inevitable panic that ensues….

Even though the “Swine Flu” pandemic was relatively mild in pandemic terms, hopefully we will use this recent experience to hone our policies for when the next pandemic strikes.

Michael