Research Summary:
Latest research looked at US Veterans to build a study population of 441,583 veterans who were infected with the coronavirus SARS-CoV-2 between 1st March 2020-31st January 2022, they had nearly 5 million non-infected people to compare this group with (controls).
They looked at the pre-delta, delta and omicron eras of infection with SARS-CoV-2 and showed that the risk of Long COVID decreased over the course of the pandemic from 10% to 8% in unvaccinated persons.
Vaccinated people had roughly half the risk of developing Long COVID, 28% of this reduced risk was attributed to a change in the virus (the variants) and 72% attributed to the vaccine but that the risk of Long COVID remained high with a SARS-CoV-2 infection even amongst vaccinated people.
Looking at the nature of the Long COVID, there was a higher risk of gastrointestinal, metabolic and musculoskeletal disorders during the omicron era than during pre-delta and delta eras combined amongst unvaccinated people. This risk was not present in the vaccinated; despite this the overall risk of Long COVID was still lower.
An important point made was despite the lower risk of Long COVID during the omicron era, because this was such a transmissible and infectious variant of SARS-CoV-2, large numbers of people have been infected and reinfected with a poor uptake in vaccination which may result in a high number of people with Long COVID.
Significant limitations were the population studied was of older white men
This was an observational study subject to biases such as undiagnosed COVID cases which could have been misclassified as non-infected controls.
The risk of developing Long COVID after reinfection was not studied.
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