Influenza during COVID-19 – Expert Briefing

The Science Media Centre hosted an online media briefing with Dr Sue Huang and Associate Professor Nikki Turner to talk about the current influenza season, vaccination uptake and what impact COVID-19 will have.

Dr Sue Huang, director, WHO National Influenza Centre, ESR
Associate Professor Nikki Turner, director, Immunisation Advisory Centre

The full briefing is available here.

What are we currently seeing in terms of influenza in New Zealand and how does that compare to the same time last year?

Sue Huang

“I have to say that the lockdown works not just for COVID-19 but also for flu as well. Since the lockdown happened we’ve only had very very low flu activity in New Zealand at the moment. In the last four weeks, we’ve had about ten influenza cases reported to ESR. In comparison to last year for example, during the same period, we had 388 flu cases reported to ESR. So you can see it is very very low at the moment in terms of our flu season.

“And you have to remember last year overall it was quite low flu activity, and in this comparison we are almost 40 times less than last year’s activity. So at the moment, it’s very quiet in the flu area.”

What do you think flu numbers might look like over the coming weeks or months?

Sue Huang

“I think flu is always notoriously difficult to predict. Sometimes you have high seasons, sometimes you have low seasons. It is all related to what is the susceptible population in New Zealand, people’s immunity levels and also people’s behaviour as well.

“If we establish good personal hygiene after the lockdown, using hand sanitiser and very frequent handwashing or coughing in the elbow, and people social distancing from those people coughing or sneezing, we can potentially maintain this kind of low flu activity into the season.

“But this is really difficult to say though because in many years we have a surprise, sometimes high, sometimes low, but the key is really to maintaining good personal hygiene and social distance.”

Where does our flu come from every season? Is that something that’s already circulating in New Zealand or does it come from overseas?

Sue Huang

We do this ongoing monitoring for flu during the wintertime when it tends to be prevalent, and especially around the end of the flu season we look at all the viruses circulating around the whole season, particularly paying attention to those viruses at the tail end – we call that the ‘hero wave’. Because those viruses tend to maintain and come back during the following year’s flu season, so that’s how we make our flu vaccine strain selection based on the pattern of the viruses.

“Another thing is, often during our summertime, which is the northern hemisphere’s wintertime, when people come into New Zealand to visit us they will bring some of the northern hemisphere viruses into New Zealand. So basically, we have two kinds of seeding viruses for the season: one is from the very end of the last year, and also coming from the northern hemisphere’s wintertime when they come to visit us.”

Do you think that the border restrictions that we’ve had for the past few months in New Zealand might have some effect on what flu strains are coming into New Zealand?

Sue Huang

“Oh yes, definitely. Every year it’s become a real pattern when northern hemisphere people come to visit us they always seed the virus through our summertime. And this year, during the last four weeks since the lockdown we’ve only had ten flu viruses detected and this is probably related to not many people coming to visit New Zealand. Particularly, for example, the last two or three weeks, we have pretty much zero of the viruses reporting to us and that is probably directly related to the lockdown blocking people coming to New Zealand.”

How and when the flu vaccine is chosen each year? Do you think the strains that have been chosen look like the vaccine will be effective this year?

Sue Huang

“In terms of flu vaccine strain selection, the key is for us to find the vaccine strains which match the circulating strains. So every year around the end of the flu season we look at the epidemiology of the viruses – basically what is the predominant strains circulating in the community – and also whether the virus has changed, drifted virologically, and also look at whether we have the availability of vaccine strains. Also the information about vaccine effectiveness, which is real-time. We also have a few trials to look at people’s immunity levels, whether the previous year’s vaccine strain can still have good antibodies against the current circulating strains. So it’s a complicated process.

“Currently we have H3N2 and H1N1 viruses circulating, which are all covered by the flu vaccine, so I would say it’s quite early on, we don’t know if it will change or not, but based on our previous studies we would be confident in many ways the vaccine has been covering all these circulating strains.”

What might the flu season look like, given what we’re already doing around COVID-19?

Nikki Turner

“Firstly we cannot predict flu seasons and I wouldn’t try. Certainly we have less coming in internationally because of our border control, but there is always flu circulating in New Zealand. So we will have a flu winter season, we just don’t know how bad it is or when it will arrive.

“With the lockdown and the increase in social distancing, we are clearly having a much lower rate of respiratory illness which is fantastic for all of us. New Zealand has learnt very rapidly the advantage of handwashing, social distancing, staying home when you’re sick. For our traditional flu messages, the COVID messages have sped up what we’ve been saying for a long time.”

How is the flu vaccine uptake tracking?

Nikki Turner

“Uptake is way higher than we’ve ever had before. From the 1st of May, for our population over 65, we’ve had nearly 60 percent of the population vaccinated – which may seem low, but last year it was just over a third. I would still like to see us do better, but we’re doing better than we ever have before. Clearly the message is out there that even though we can’t protect ourselves against COVID, we can protect ourselves against influenza and other vaccine-preventable diseases.

“Of course the downside of that is that we have struggled with the supply and demand issues. You project how much flu vaccine you need well before the season, and they make the Southern Hemisphere supply. So New Zealand last year projected that we would have increased demand this year, and ordered an extra ~400,000 doses. But that was well before COVID arrived, and of course the demand is looking like it’s going to outstrip that. That’s the main reason it’s been quite bumpy out there in ‘provider-land’, in being able to ensure that all providers have a smooth supply of flu vaccine at all times. We’ve actually done a provider survey which suggests 50-55 percent of providers have been fine but up to nearly 20 percent have had significant problems accessing the vaccine.

“We’ve also heard maybe up to 50 percent of the population have been reluctant to come out and get the vaccination, particularly the elderly, because of the fears around being in contact with COVID. So the really important message is that our practices and pharmacies have adapted so rapidly to this new environment to ensure that particularly those who are most vulnerable are safe to come get their vaccine. But there are still reports of people who are scared to leave their homes and come and access these vaccines.”

If that’s the case, should we still be focusing on vulnerable groups for the flu vaccine?

Nikki Turner

“My opinion is that it’s really important to focus on those most vulnerable. It’s really hard to predict how high community demand will be, and if you just allow everybody to have a vaccine New Zealand would run out. On the other side you don’t want to end up with large supplies of vaccine you don’t use so it’s a very difficult balance. The ministry has been consistently saying we must really push those who need it the most and also front-line providers.

I also recommend family members and close contacts of the vulnerable. those are the next group of people who we should focus on vaccinating. The vaccine doesn’t work very well often for the very elderly and for some people with significant medical problems, so vaccinating close contacts – those in the rest homes, family members, caregivers, and front-line services.

“Because flu isn’t in high rates at the moment, and we have been in lockdown, and we’re only slowly moving back, we’re not expecting to see large amounts of flu for the next few weeks. So there’s no rush to vaccinate the healthy well population at this stage, while we’re waiting for new supplies to arrive.”

What does an average flu season in NZ look like and how is COVID affecting the current one?

Nikki Turner

“Flu is a significant illness and we have always underestimated it. Our modelling projections are around about 500 people a year will die from flu-related causes, which is huge. The modelling suggests it’s about 1.8 percent of deaths every year. The extra whammy of COVID is that there is no immunity, so when you catch COVID, you don’t have any protection – whereas with flu, most of us have been exposed to it year-in year-out for a long time so we have some degree of protection. That’s why we’re all so scared of flu pandemics and that’s why COVID is so much more significant.”

Do you have concerns about any other aspects of immunisation? Are we keeping up our vaccination rates during this time?

“We have significant concerns. From a recent front-line vaccinator survey we’ve done, at least 50 per cent report that families have not been coming in on time – both for flu vaccine and for childhood vaccine – out of fears around COVID. Internationally there is enormous concern, particularly in lower-resourced countries, that the childhood vaccination programme is getting delayed. We have got really significant issues that these diseases could come back, and the real killer is measles. As many of us know, we really struggled with measles in New Zealand last year. Internationally, it does not take much for a childhood programme to get delayed and measles to return and we could well see there will end up being more deaths in our childhood population from measles than from many other issues.

“Within New Zealand, at this stage, we’re seeing a small dropoff over the lockdown period. It’s hard to estimate yet, but maybe 1-2 per cent delay in vaccination. I’m really hoping, and we’re feeling reasonably confident, that New Zealand providers are onto it now and actively re-calling, our outreach services are up and running and a really strong message for us is: we can’t let this slip, we can’t stop, we can’t delay, we have to get our childhood programme going or else we’re going to be in problems for a whole lot of other reasons.”

For those of you that have been working in public health and dealing with infectious disease for many years over your careers, the core messages haven’t changed – we’ve been hearing the same things about good hand hygiene, about coughing into our elbows – how does it feel to see people taking that seriously – and what is your expectation for how that will look as we start to come out of lockdown?

Nikki Turner

“There’s many answers to that, I think the saying ‘crisis is opportunity’. One would never have wished COVID on our community or on the world, but currently, we’ve certainly overnight, rapidly as a community, learnt a lot about infectious diseases. I feel our community have never taken flu seriously enough in the past, and neither has the world. So this is one incredibly unfortunate way of making us all sit up and realise the importance of infectious diseases.

“I think some of the messages will stay. I think the hand hygiene, social distancing, the awareness that when we’re unwell we have to stay home. Those messages will last. I think the message I’d love to see last is that we are a community, we’re not a pile of individuals, and that – as we’ve seen with the international news – the disparate awareness of the fact that we have to walk as a community and what that means to us. I feel really proud of New Zealand that we’re often accused of being a country of individualists, and yet we have reached the awareness that infectious diseases, as much as anything else, show us that we are community and these bugs spread between us.

“So some of these messages will certainly stay on, I feel very confident about that. On the downside, the equity issues are becoming very scary. Many people, particularly in countries less resourced than us, are not in a position to take awareness of social distancing and how to manage your own safety. So I think the scary thing for the world is the rapidly-increasing equity gaps and thank god New Zealand is in a better position than many. I’m very thankful to be here.”

Sue Huang

“I want to conclude the same sentiment. I think we as a country we are doing really really well. I often feel quite emotional watching the numbers day after day and the Government’s decision to lockdown as early as possible. Which makes such a big difference. Look at what’s happening at the moment in the USA, what happened before in Italy and Spain. We avoided that and that is fundamentally important. And as a community, as a society, we actually go along, we follow our leader and we make sure we social distance and we maintain that behaviour, which made a big difference. To have the number to zero, that made me very emotional. So that’s really great.”