Thanks I appreciate the summary—better than anything else I could find on the internet, as is so often the case on this forum.
One small point is that there has been a long history of H5N1 infecting small numbers of humans, with limited human to human spread, without the virus mutating to become highly contageous. https://www.cdc.gov/flu/avianflu/h5n1-human-infections.htm. This suggests to me that the chances of the virus mutating to become highly contageous might be lower than is intuitive.
Also the fact that there are already 4 vaccines—although high rates of vaccine hesitancy may now unfortunately be established in the population.
I’ve spoken to some virologists who think the probability of it becoming a pandemic is low. However even tho there has been limited human spread for years, I am not aware of outbreaks rather than very limited infections among other mammals in past outbreaks like we are seeing now. I’m getting pretty worried, although I haven’t yet come up with probabilistic predictions.
Also one thing I am not clear on is the efficacy of tamiflu or whether focusing on increasing tamiflu supplies might help.
Tamiflu is oseltamivir. CDC has info on antivirals and vaccines for H5N1 and H7N9.
Tl;dr: we have 3 antivirals, but some evidence of resistance, and a small stockpile of candidate vaccines, though the virus mutates fast.
Antiviral Drugs Can Be Used to Treat Illness
CDC currently recommends treatment with a neuraminidase inhibitor for human infection with avian influenza A viruses. Analyses of available avian influenza viruses circulating worldwide suggest that most viruses are susceptible to oseltamivir, peramivir, and zanamivir. However, some evidence of antiviral resistance has been reported in HPAI Asian lineage avian influenza A(H5N1) viruses (“Asian H5N1 viruses”) and Asian lineage avian influenza A(H7N9) viruses (“Asian H7N9 viruses”). Monitoring for antiviral resistance among avian influenza A viruses is crucial and ongoing.
U.S. Government Stockpiling Asian H5N1 and Asian H7N9 Vaccines If Needed
The United States federal government maintains a stockpile – vaccines, including vaccine against Asian H5N1 and Asian H7N9 viruses. The stockpiled vaccines could be used if similar viruses were to begin transmitting easily from person to person. Since influenza viruses change, CDC continues to make candidate vaccine viruses as needed. Creating a candidate vaccine virus is the first step in producing a vaccine. More information about “Making a candidate Vaccine Virus (CVV) for a Highly Pathogenic Avian Influenza (Bird Flu) Virus” is available.
Thanks Monica! I suppose the big question is, do outbreaks among mammals make future outbreaks among humans more likely. Intuitively it might seem so, but I can’t think of other examples off the top of my head where there was a known and tracked outbreak of a non-human affecting disease among mammals, which then mutated to become a very contageous outbreak among humans. There may well be cases though I’m unaware of.
This is very different from diseases like the plague, or sleeping sickness where the host animals such as rats or cows spread the disease directly to humans.
Very keen to hear examples if anyone knows of them.
The main concern now is that we’re seeing unprecedented likely mammal-to-mammal spread. I don’t know what seems intuitive to most people, but this is the reason for heightened concern around the issue. Whatever your priors were before, this should probably update you towards a bigger risk of human-to-human spread.
Yes they do update me to a higher risk of human to human spread. Human to human spread however has happened a number of times before, yet has never got out of hand. This pattern over the last 10 years. could perhaps update us towards a smaller risk of highly contageous spread between humans.
Of course we should take this seriously, and we may well not be taking it seriously enough right now. Knowing the history of a disease is important though, as this is not a new disease and is more likely to follow past trends than new noes.
Full agree! A track record of human-to-human spread with limited transmissibility is an update against a change in that area, and a new event of rapid mink-to-mink spread is an update for. Not sure how to balance them out mathematically, but it’s important to keep both in mind.
Also, with regard to human vaccines, my understanding is they’re in low stock and only tested for seroconversion, since we don’t use them widely enough to get direct data on efficacy. We also have poultry vaccines but don’t use them widely, and it seems their effectiveness is inconsistent. So much to be improved on in the realm of H5N1 vaccine tech.
Thanks I appreciate the summary—better than anything else I could find on the internet, as is so often the case on this forum.
One small point is that there has been a long history of H5N1 infecting small numbers of humans, with limited human to human spread, without the virus mutating to become highly contageous. https://www.cdc.gov/flu/avianflu/h5n1-human-infections.htm. This suggests to me that the chances of the virus mutating to become highly contageous might be lower than is intuitive.
Also the fact that there are already 4 vaccines—although high rates of vaccine hesitancy may now unfortunately be established in the population.
I’ve spoken to some virologists who think the probability of it becoming a pandemic is low. However even tho there has been limited human spread for years, I am not aware of outbreaks rather than very limited infections among other mammals in past outbreaks like we are seeing now. I’m getting pretty worried, although I haven’t yet come up with probabilistic predictions.
Also one thing I am not clear on is the efficacy of tamiflu or whether focusing on increasing tamiflu supplies might help.
Tamiflu is oseltamivir. CDC has info on antivirals and vaccines for H5N1 and H7N9.
Tl;dr: we have 3 antivirals, but some evidence of resistance, and a small stockpile of candidate vaccines, though the virus mutates fast.
Thanks Monica! I suppose the big question is, do outbreaks among mammals make future outbreaks among humans more likely. Intuitively it might seem so, but I can’t think of other examples off the top of my head where there was a known and tracked outbreak of a non-human affecting disease among mammals, which then mutated to become a very contageous outbreak among humans. There may well be cases though I’m unaware of.
This is very different from diseases like the plague, or sleeping sickness where the host animals such as rats or cows spread the disease directly to humans.
Very keen to hear examples if anyone knows of them.
The main concern now is that we’re seeing unprecedented likely mammal-to-mammal spread. I don’t know what seems intuitive to most people, but this is the reason for heightened concern around the issue. Whatever your priors were before, this should probably update you towards a bigger risk of human-to-human spread.
Yes they do update me to a higher risk of human to human spread. Human to human spread however has happened a number of times before, yet has never got out of hand. This pattern over the last 10 years. could perhaps update us towards a smaller risk of highly contageous spread between humans.
Of course we should take this seriously, and we may well not be taking it seriously enough right now. Knowing the history of a disease is important though, as this is not a new disease and is more likely to follow past trends than new noes.
Full agree! A track record of human-to-human spread with limited transmissibility is an update against a change in that area, and a new event of rapid mink-to-mink spread is an update for. Not sure how to balance them out mathematically, but it’s important to keep both in mind.
Also, with regard to human vaccines, my understanding is they’re in low stock and only tested for seroconversion, since we don’t use them widely enough to get direct data on efficacy. We also have poultry vaccines but don’t use them widely, and it seems their effectiveness is inconsistent. So much to be improved on in the realm of H5N1 vaccine tech.
*H5N1
Changed thanks nice one!