COVID-19 is notorious for its broad and unusual array of symptoms, and with a new variant taking the world by storm, some scientists have started seeing reports of a new symptom: night sweats.
The strain currently driving a significant rise in cases around the world is the subvariant BA.5, sometimes known as the “sibling” of the Omicron variant. Together with BA.4, these two subvariants have now become the dominant strain of the virus.
Some researchers also believe it may present with subtly different symptoms than other variants.
“One extra symptom from BA.5 I saw this morning is night sweats," Professor Luke O’Neill, a Professor of biochemistry from Trinity College Dublin, told Irish radio station NewsTalk.
“Isn’t that strange?" he added.
The subvariants are masters of evading the immune response, meaning that people who have already been infected with SARS-CoV-2 can still fall sick a second time (and even a third time). Fortunately, early evidence suggests the BA.5 subvariant may be similar to its Omicron cousins in that it causes less severe disease and death than previous variants, like Delta, but its ability to reinfect is a cause for concern.
The reason for the different symptoms, Professor O’Neill explains, is partially due to genetic changes to the virus, but also the way our immune system reacts to an infection.
“The disease is slightly different because the virus has changed. There is some immunity to it – obviously with the T-cells and so on,” O’Neill added. “And that mix of your immune system and the virus being slightly different might give rise to a slightly different disease – with strangely enough – night sweats being a feature."
Professor O’Neill also stressed the importance of being fully vaccinated to ward off the most severe potential impacts of the infection.
There’s not much data on how common the symptom of night sweats is. According to the ZOE COVID Study app, the most reported COVID symptoms among vaccinated people (two doses) include: runny nose, headache, sneezing, sore throat, and persistent cough. Other symptoms that were previously much more prominent – such as loss of smell, shortness of breath, and fever – are now less commonly reported, ranking way down the list of most common symptoms, at 6th, 29th, and 8th respectively.