Reacción a "Reactions: persistent covid studies have created misunderstandings because of their limitations, says analysis"

There is no doubt many people have developed a serious post condition following their infection with SARS-C0V-2. The numbers are large because of the unprecedented SARS-Cov-2 infection numbers worldwide - now approaching 800 million. The BMJ paper highlights an important problem as we move forward to understand better the extent and long-term effects of the mixture of conditions classified as Long COVID.

The World Health Organization moved quickly to establish a clinical case definition for what was known to be a heterogeneous group, at the very least containing people with ongoing organ damage, and groups with a classic post viral fatigue condition reminiscent of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS). Despite this, it was surprising that supposedly well researched papers have come out with a huge range of 10-50% of those with COVID, although more recently it has dropped in some publications below 10%, with variants like those of the Omicron group causing a lower incidence.

Hence, there has been a pressing need for better definition with precise controls and diagnosis of the Long COVID condition and in this sense the BMJ paper is a timely reminder. Particularly pressing is to have clear definition of the clinical phenotypes. A very recent paper defined four clinical phenotypes, a post viral fatigue syndrome like ME/CFS, a respiratory syndrome, a pain syndrome, and a neurosensory condition in a ratio of ~4:2;2;1. So, the need as outlined in this BMJ paper for better definitions and precise controls so targeted help for families, communities, and countries can be better defined, is timely.

The call not to divert precious funding towards Long COVID and away from other needs - while having vaildity - ignores the fact that for decades the collective group of post viral syndromes (ME/CFS) has been poorly resourced, and the affected largely ignored. This new interest in Long COVID has benefits for those people who have been living with such debilitating conditions for many years. But the BMJ paper principle is important in that these affected people may have even less support if the focus is totally on Long COVID. But it would be a tragedy if those affected with Long COVID become another subgroup of the ‘missing millions’.