As we all remember, during the pandemic COVID science and the downstream policy decisions were being made on the fly. Then after mass vaccination, public interest largely moved on.
The science, however, has not stopped: COVID remains one of the most significant areas of public research spending worldwide. With it, our understanding of the disease continues to advance.
Here are five surprising new discoveries about COVID you might have missed.
COVID may harm the immune system
In the early days of the pandemic, infection with the SARS-CoV-2 virus was considered equivalent to being vaccinated in terms of immunity. You might remember that a certificate confirming having been infected was accepted in the same way as a vaccination certificate.
We now know, though, that that wasn’t precisely the case. In fact, vaccinated people who have never been infected with COVID show higher levels of anti-COVID immune-system T-cells than people who have had COVID but have never been vaccinated. Even those who had been infected with COVID and then were vaccinated had less immune activity than those who dodged the virus entirely before vaccination. Researchers suggest infection with the COVID virus specifically damages the functionality of the immune system.
An overall decrease in lymphocytes during COVID-19 has prompted some hyperbolic comparisons with HIV. However, COVID’s effects appear to be shorter-term and reversible. Indeed, the science is ongoing and some research has contested the theory of “T-cell exhaustion” due to COVID infection.
Cognitive impacts
COVID-19 is now firmly known to cause cognitive dysfunction. This typically lasts weeks but may persist months after initial infection.
Changes in the brains of patients reporting COVID-related “brain fog” can be detected using neuroimaging scans. These include changes to both density and connectivity of brain tissue.
Researchers found that the spike protein accumulates in the hippocampus, negatively impacting the functioning of the synapses and potentially setting in train neurodegenerative processes. These may be off-set by metformin.
Gender, anemia and long COVID
Women are three times more likely to develop long COVID than men. The gender disparity of long COVID patients roughly matches the gender disparity seen with chronic fatigue syndrome.
It is still not well understood why long COVID develops. However, research comparing women who did and did not go on to develop long COVID after infection with SARS-CoV-2 showed the long COVID patients had on average lower testosterone, more problems with gut inflammation and “leakiness”, lower red blood cell count and were more prone to anemia. These factors, and especially anemia, have been described elsewhere as predictive of long COVID risk as early as a patient’s admission to hospital.
The future of simultaneous flu and COVID vaccines
Combined flu and COVID vaccines may turn out to be ineffective. The mechanism is complex but seems to relate to elevated levels of interleukin-6 and -8 in the aftermath of flu vaccines. These have been negatively correlated with the persistence of anti-COVID antibodies in the blood at follow-ups after 3 and 6 months. It should be noted that this study is far from definitive, as such combined vaccines are still undergoing clinical trials.
Smell detection
COVID can be detected with an 80% success rate by sampling sweat. That’s the outcome of Mexican government backed research that aimed to test whether dogs could be trained to detect COVID-positive patients.
Vaccine safety
COVID vaccines are now the most extensively researched vaccines ever and their safety record is impeccable. The most high-profile concern has been myocarditis, or a swelling in tissue around the heart.
At the population level, this occurred in 0.85 more people per 100,000 in the six months following vaccination. This increased risk is, however, three times lower than the increased risk of myocarditis following COVID infection itself. So the cost-vs-benefit ratio of COVID vaccines has proven to be outstanding.