THERESE RAPHAEL: Covid-19: lest we forget the flu

On the list of things to worry about in the age of Sars-CoV-2, boring, old winter flu probably doesn’t rank high. Especially not in the middle of a summer heatwave. And yet it should.

Humanity has grown so accustomed to annual waves of influenza that it was the baseline comparison when Covid-19 first arrived. (It’ll be just another flu, we said.) The implication was that levels of influenza sickness, hospitalisation and death were acceptable, even inevitable. 

I was certainly guilty of that thinking. Though my employer offers an annual flu shot, I sometimes didn’t bother to get it. But the pandemic has exposed the weakness of our attitudes and policies towards influenza. We now have an opportunity to do things differently. This isn’t an argument for flu-driven lockdowns or a national paranoia about any bug. But we can build better defences against influenza at relatively little cost, and for a gain in lives and healthcare capacity.

One reason to get more serious about flu is its cost, both economically and in human terms. Annual costs of treating influenza (routinely in excess of $10bn in the US) are significant, even when you just look at hospital outlays for those most severely affected.

Influenza epidemics in the northern hemisphere affect anywhere from 5% to 15% of the population every year. On average, about 8% of the US population gets sick from flu each season. For most, it’s usually a mild, if unpleasant experience. But for some, it can be deadly.

The US Centers for Disease Control estimates that, on average, 36,000 people have died of flu each year over the past decade, with 61,000 deaths in the 2017-2018 flu season. In the UK, the average is about 17,000 annual deaths. Obviously, Covid-19 is a different order of magnitude, but the costs to the healthcare system from flu aren’t trivial.

The elderly are most vulnerable to flu, but so are pregnant women, very young children and those with other medical conditions and weakened immune systems. Some who contract and recover from flu end up with post-viral symptoms that drag on. Long Covid-19 has showed us just how debilitating these can be.

What happens when you layer flu on top of Covid-19? We don’t really know, since last winter saw an incredibly mild flu season, mostly due to measures such as lockdowns, social distancing and masking. Infections rates for flu were two-thirds lower than during the 2011-2012 season, which had record low rates.

We can’t count on a repeat. The low prevalence of flu last year makes it harder to predict which strains to include in this winter’s vaccine. We could get lucky again, or things could get worse: lowered levels of natural immunity after a few low-flu seasons could make it easier for new variants to take hold.

Britain, with its overstretched national healthcare system and gargantuan backlog of surgeries and other procedures, can scarcely afford a bad flu season. Consultations for influenza-like illnesses take up substantial GP time and hospital capacity in a normal year. High rates of flu on top of Covid-19 would be a strain too far, requiring substantial new government resources and leaving many people without treatment.

But it’s not just the compounded health burden that should make us rethink influenza. The fact is, we have been far too complacent about flu for too long. Many flu deaths are preventable with jabs and the kinds of behavioural modifications we’ve grown accustomed to from Covid-19.

Not only did the social-distancing measures imposed during the pandemic decrease the spread of flu, they’re also estimated to have led to a 20% drop in the common respiratory syncytial virus (RSV) in the US. RSV accounts for 5% of the deaths in children under five globally. The problem now, however, is that the recent lifting of Covid-19 restrictions has coincided with unseasonably high RSV cases in the US. 

Higher levels of flu vaccination would be a game-changer. Last winter, the number people opting for a flu vaccine in Britain reached record levels, with the National Health Service vaccinating more than 80% of those over 65 — 10% higher than the previous year and ahead of the WHO goal of 75% for the first time.

But the vaccination rate drops off with the young. Less than 45% of those under 65 with one or more underlying risk factors gets vaccinated. Though more than 2.5 million children were vaccinated through school programmes, that’s still well under half (47.5%) of all children. Uptake also varies across ethnic groups, with some minorities lagging in getting vaccines. In the US, black communities (where vaccine rates are about 41%) had the highest flu-related hospitalisation rate of any ethnicity.

A study at the University of Bristol is seeking to determine what side effects people get when given the recommended flu vaccine along with either of the vaccines. Getting a joint Covid-19 booster shot and flu shot could ensure that there is more flu vaccine coverage.

Of course, the effectiveness of flu vaccines can vary from one season to the next and from person to person. They are normally between 40% and 60% effective when they match up well with the variants circulating.

So we’d be well served to also apply our Covid-19 habits to illnesses such as flu. That might mean more hybrid working during peak flu months or if there’s an outbreak. Masking at certain times, even if not compulsory, makes a lot of sense too.

If Covid-19, like flu, is going to be a recurrent seasonal affliction — as seems probable — we will need to better manage the pressure on the health systems during the winter. That means being prepared to finance higher levels of care during these crunch periods or doing more to reduce the strain on the system. We’ll most likely never eliminate influenza and other viruses, but we can make winters less costly and less miserable by raising the bar on an illness that many of us treated too casually.

Bloomberg Opinion. More stories like this are available on bloomberg.com/opinion