Concerns of improved transmissibility and flawed guidance in new Andes virus
I do not wish to come across as alarmist. I have research experience with and publications on SARS-CoV-2 but have been working in autoimmunity since 2024. I hope we can avoid the same early improper assumptions made with COVID, but I fear public health guidance has already dropped the ball by telling mainstream media that the virus is not mutated and that it does not spread easily through air. Within the virology and epidemiology community, I have seen a surprising lack of disregard for certain facts.
The dogma since the release of the Swiss patient’s Andes virus sequence has been that the lack of reassortment is evidence that the virus does not have significant or consequential mutations. This is obviously false and anyone who has taken an infectious diseases or virology course should know this.
There are indeed mutations in the M segment, including in the regions coding the receptor-binding Gn and Gc proteins. It is not known if these mutations are consequential for human transmission, but it can’t be said that it’s impossible. Though it is rare that such a beneficial mutation would occur within an animal reservoir, it can happen. Keep in mind that SARS-CoV-2 gained its furin cleavage site before it started spreading in humans. But this is a very rare occurrence and I’m hoping it isn’t what happened here, though the spread on the ship gives me pause.
Lytras analysis does not show convincing evidence that genetic differences in the surface proteins would not confer improved human-to-human transmissibility. It is also not evidence of the contrary.
I wouldn’t write off the genetic distance between the Epuyén virus with the Swiss-resident virus. For example, SARS-CoV-2’s high transmissibility is attributed largely to the furin cleavage site, which was not present in more closely related coronaviruses, but was indeed present in some that were more distantly related.
The most genetically similar virus only spread to household members and healthcare professionals in direct contact with the index patient (Martinez-Valdebenito, 2014). However, the Andes virus from the Hondius appears to spread more easily. I understand that they were on a small cruise ship, but there was transmission thought to have occurred from brief “passings by”, which seems to align more closely with the manner of spread of the 2018-2019 outbreak in Epuyén, Argentina. It also seems that the incubation period is shorter than previously described.
Still, cruise ships are unique environments. There are so many factors including shared serving utensils, poor air circulation, close sleeping quarters, potential swinging, etc. That may not sufficiently explain (in my opinion) the differences in spread and incubation period.
Anxiously awaiting good news that those on the Hondius do not spread the virus as it spread on the ship, but I can’t help but hold my breath.
Please share your thoughts and pertinent new information as it becomes available.