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A presumptive case of H5N1 influenza has been reported in a teenager from British Columbia. Confirmatory testing is underway. Very little additional information has been released, so it’s hard to say how surprising and concerning it is. Information vacuums like this often lead to excessive speculation, but information sharing has to be balanced with privacy of medical information, and we don’t have an automatic right to know everything about a case immediately. It also takes time to properly investigate a case, and there’s often (understandable) reluctance to release very preliminary findings where there are still a lot of unknowns. Hopefully some reliable details will be released soon as the investigation continues.
A few key things that we’d like to know include:
- What was the source of the virus in this person? The government release indicates “The source of exposure is very likely to be an animal or bird, and is being investigated by B.C.’s chief veterinarian and public health teams.” The lack of a specific statement that this was linked to a known poultry infection has led some to questionable messaging. A ProMedMail report said “Based on the details provided, it would seem the individual did not have direct contact with infected cows or poultry” which seems to be a questionable (bordering on irresponsible) overstatement at this early point in the investigation. It might be true, but it’s way to early to raise concerns about unknown exposure routes, especially given there are active cases of H5N1 in poultry in this region.
- What strain is the virus in the person? Presumably it’s the circulating wild bird strain (vs the strain circulating in dairy cattle in the US, or another strain from wild birds), but knowing more details about the strain and whether it has any relevant mammalian adaptations is important.
- Have there been any additional human cases? This takes time to determine, but it’s important to know whether this was a single isolated event with no human-human transmission, part of a cluster associated with common animal contact (e.g. on a poultry farm), or whether there was any downstream human-to-human transmission. So far, no other human infections have been identified.
- How serious was the illness in this person? The press release only indicates that the person “is receiving care at BC Children’s Hospital.” While there’s public interest in knowing how severe the infection is, that’s personal medical information, but hopefully some information will be released at some poiny. Infections in people associated with the H5N1 strain in the US have been mild, and hopefully that’s the case here too.
Ultimately, it remains to be seen if this was a rare but expected spillover to a person with known direct contact with infected birds (the most common and most reassuring scenario) or something else. The less it fits that scenario and the harder it is to explain the infection, the greater the concern.
As usual, social media has a big camp amplifying “the end is near” messaging. While it’s not good news, there’s nothing here yet that raises a lot of concern, beyond the fact that every human exposure and human infection is playing with fire, as it creates more opportunities for this virus to change and adapt to people. As I’ve said before, I’m not really concerned about the currently circulating strain of H5N1 from a human health standpoint, since it rarely causes disease in people, typically causes mild disease when it does, and is not well adapted for human-to-human spread. I’m concerned about what this virus could do if it becomes more adapted to humans, with an ability to spread effectively between people and cause more severe disease. We need to do all we can to contain it, limit spillover infections and address those that occur promptly, but we need to maintain some perspective at the same time.
Presumably more information will be released soon to help us better understand this situation.