Of course! Everybody should stay on top of annual flu shots and COVID boosters - and RSV if you are eligible - and don’t forget about routine or travel immunizations, either. Tdap for example only lasts 10 years. In my lifetime, we’ve also had new vaccines for HPV, RSV, malaria, and chicken pox/shingles, which is amazing. Vaccines are one of the cheapest and easiest ways to take care of yourself and the people around you.

Okay, re: any cross-protection from vaccines, the answer is again likely no. For years people have been working on a “universal vaccine” so we wouldn’t have to do annual shots. There is currently work being done with the mRNA technology that came out of COVID, as well as universal HA targets. But we are, for the moment, still stuck with traditional flu vaccines.

Our current flu vaccines work by stimulating the production of antibodies targeting two surface proteins of the flu virus, HA and NA. These control viral attachment/fusion and release, respectively, which are important for viral infection and replication. When we think about vaccine effectiveness studies we want to see those HA and NA titres high because they are linked with protection.

The human vs avian strains of influenza behave differently when it comes to these proteins. HA proteins of human-to-human strains recognize α(2,6)-linked sialic acid, while avian strains use α(2,3)-linked sialic acid. Not every species has tissues with both of these sialic acid receptors. Some do - like pigs, quails, and turkeys - which is where we see viruses start to shift and cause problems for humans. So, mutations in those HA proteins in avian influenza is what decides whether they can reproduce in humans.

In other words - our current swine flu “H1” vaccine is unable to target any avian flu “H1” protein, and that’s actually a good thing! It means that the strains are well and truly separate, and avian influenzas cannot readily reproduce in humans without additional mutation. If and when we start to see human-to-human transmission of H5, then we can look at that strain’s protein structures and determine appropriate targets for vaccination.

This is a question for your doctor, so I am not providing any medical advice. Typically whether from infection or vaccination, we expect to see protective antibodies for several months.

It’s one patient and these rapid changes happened before in human patients, so who knows. All other H5 outbreaks to date have been limited and sporadic. We’d need more genomic data from more human cases. They are also going to monitor these cases closely so we’ll find out more as we go.

You’re welcome!

I knew this question would come up and unfortunately (or fortunately) I’m not an immunology PhD 😅 of course it’s always recommended to get flu shots due to partial coverage, reducing coinfections, and sparing health systems undue burden but let me see if I can get you a proper answer from someone who dreams about proteins and titers.

The former! I’m not currently worried about contracting it, and neither should anyone who isn’t hanging out on an animal farm. That said, of course flu and other viruses can jump species, and flu mutates a lot faster than some other viruses. There is never any way to rule out a wild flu mutating into something that can impact human health more broadly.

To your second point about goalposts moving - I’m not sure specifically what you’re referencing, but perceived risk is inherently personal and can never be a one-size-fits-all calculation. We might have a tidy risk ratio in a paper that pertains to a certain population, but it doesn’t always translate to the general public. Typically we leave that stuff to CDC, because they have whole committees full of brilliant people to synthesize the evidence and argue about what to tell the public and how. Science changes and so do recommendations as we learn more. I would recommend getting further H5 “news” and updates directly from CDC. You can sign up for the MMWR which will have weekly stats and case details.

Former influenza epidemiologist here and the answer is probably not. Our current influenza vaccines in the US (and in almost all countries) are trivalent, meaning they have 3 strains: an influenza A H1N1 (aka swine flu), an influenza A H3N2, and an influenza B (Victoria). Fun fact, they used to include 4 strains, but COVID actually wiped out the second B strain and it hasn’t been detected since 2020.

Unfortunately, the current bird flu is H5, a separate influenza A strain. Typically there isn’t a lot of shared clinical protection overlap between genomes this different. This is why influenza vaccines typically use 3 (and formerly 4) different strains of the virus, to confer the most protection.

However, unless you work in dairy or poultry, I would not worry. I am not particularly worried. I know it’s making headlines, but only 66 human cases are in the US so far, and all but 2 had direct contact with those animals. Currently there is no documented person-to-person transmission and certainly nothing like what we saw early on with COVID.

If you want my personal take, I still mask at large events / crowded places / airplanes to avoid flu and COVID altogether. I still encourage everyone who is ill to mask and stay home, even though it’s out of fashion. I think we will see egg, dairy, poultry, and beef prices rise with H5, as farmers are forced to cull animals. Also, we may see cases from raw milk and backyard animal husbandry - please don’t drink raw milk, pet cows, kiss chickens, touch dead birds without gloves, etc. right now and you probably won’t get bird flu.

Hope that helps, happy to answer any other influenza or respiratory infectious disease Qs!

Edited to add: The fact we have human cases at all is because farm workers - usually immigrants with limited English - are routinely exploited, denied PPE, or put at risk in unacceptable ways. Farms are basically self regulated in the US, though they are officially regulated by the USDA. It is extraordinarily difficult to get farms to cooperate with pandemic preparedness. You have to pay them federal money to do anything. There have been documented cases of farm workers being told to cull infected birds with zero PPE, and that’s unacceptable. These vulnerable people are the ones paying the price for our H5 knowledge right now, and it’s not right. It’s disheartening to have worked on pandemic preparedness for decades, fumble COVID altogether, and still fail to prepare for the next one. As climate change continues unmitigated we expect to see more human-wildlife interaction and more zoonotic diseases. We can’t just do good science; we also must address workers’ rights, capitalism, and climate change.