What the epidemiology of glandular fever might tell us about ME/CFS

[Hutan]

There is quite a lot of evidence that severity of illness is important in the risk of ME/CFS post infection:

I'm not convinced about the idea of a more severe illness being a predictor of ME/CFS.

We haven't seen that with Covid-19. Lots of people seem to get ME/CFS after a mild illness.

I've commented elsewhere that I'm not sure that the Dubbo study authors were right when they drew that conclusion about the correlation with illness severity. There was a gap between illness onset and the first contact with the researchers. So, what they observed possibly was just that people still reporting symptoms 6 weeks or whatever it was after illness onset were more likely to report persisting symptoms at 6 months. The measure of illness severity wasn't hospitalisation.

The example of Peter White that you give is along the same lines. Persisting (ME/CFS) symptoms could make it seem like the acute illness had a long duration, but it doesn't necessarily mean that the infection was a life-threatening one. Illness duration isn't the same as illness intensity.

 

[Mij]

I didn't have severe symptoms during sudden viral onset M.E. even though I had 'extremely' elevated anti-thyroid antibodies. I had positional vertigo for 3 days, grinding gut sensation, and a mild sore throat and ear for several months. I didn't feel well but I was still able to go to school and continue some level of exercise. I didn't have PEM back then.

 

[Wyva]

I just saw this Hungarian study and thought it was interesting. It is not about EBV but cytomegalovirus (CMV), which is very similar and closely related to EBV and can also cause mono/glandular fever (although EBV is responsible for 90% of the cases, according to Wikipedia).

Large-scale seroepidemiology of human cytomegalovirus (CMV) in Hungary (2010–2024), 2025, Balázs et al

https://akjournals.com/view/journals/030/72/4/article-p380.xml

I copy some parts of the discussion section. There are some interesting explanations for gender and regional differences:

In this study, the seroprevalence of CMV-specific IgG antibodies was assessed in 13,761 individuals aged 0–97 years from South Transdanubia, Hungary. Overall 69.2% of the participants were found to be CMV IgG seropositive, a proportion comparable to the estimated prevalence of 66% in the WHO European region [18], but lower than 84–86% reported by Varga et al. [23, 24].

The seroprevalence increases with age, consistent with other international studies. Approximately 40% of the infections occurred within the first five years of life, and half of the estimated population were seropositive by 25 years. These findings indicate that the most infections occur in childhood and early adulthood, in agreement with previous reports [2, 3]. The women seemed to be more affected in line with Varga et al. [22, 23]. Perhaps the reason for this is that women are the primary caretakers of children whose bodily fluids are the main source of the infection [2, 3]. Interestingly, we observed a slight decrease in the percentage of seropositivity between 2020 and 2023, but significance was only found in two age groups (21–25 and 51–55 years) and not associated with sexes. The cause of this phenomena is unknown, but two factors i) restrictions and containment measures during the SARS-CoV-2 pandemic and the ii) increased number of specimens in this time period could affected to the statistical results. Possible changes in CMV seroprevalence needs to be followed up in the future. Otherwise decreasing trend (∼4%) was also observed by Gorun et al. [20] in Romania comparing two cohorts of pregnant women from 2008 to 2010 and 2015 to 2018.

There could be several reasons why our observed seropositivity is lower (69.2%) than 84–86% that observed by Varga et al. [22, 23]: i) there was a higher proportion of samples from overrepresented older age groups in the Varga et al. study which may have increased their mean CMV IgG seroprevalence value comparing to ours. This may be confirmed by the fact that Mihály et al. [24] found a lower (65.4%) seropositivity rate among pregnant women between age 18 and 46 years, ii) Varga et al. used samples collected between 1998 and 2007 which does not overlap with the sample collection period of our study; iii) our study only represents one region (South Transdanubia) of Hungary and we should notice the correspondence between CMV prevalence and socioeconomic status therefore prevalence can vary in differentially developed regions within one country.

A specific group of interest related to CMV is women of childbearing age. The women between 16 and 45 years showed a 61.2% seropositivity in our study which means 38.8% of these examined women are not protected against a primary CMV infection. The ratio of unprotected women of childbearing age are higher (44.8%) under 30 years. The high (65.2%) seroprevalence among children under 1 year mostly also represents the women in child-bearing age due to the presence of maternal CMV IgG antibodies. These results are in line with Mihály et al. [24], who found a 65.4% seropositivity rate among pregnant women. Comparing with available studies from Europe, our results place between Germany (56.7%) and Poland (81.9%) [17, 19].

Transdanubia is indeed the "wealthier" part of the country. It is in the western half of the country while the poorer, more backwards regions with lower socioeconomic status are in the eastern half. The latter also includes counties known for having large Roma populations living in poorer conditions. Roma populations tend to be more close-knit, traditional and have significantly lower socio-economical status, which may also affect seroprevalence.

So if this can indeed affect seroprevalence, I can absolutely believe there might be a regional difference between the two halves of the country (and other parts of the world elsewhere). My theory is that maybe socio-economic status also correlates with how often people share food and drinks with each other, including with their kids. And maybe that affects seroprevalence somewhat.

It is also interesting to see the difference in seroprevalence of CMV in women of child-bearing age in different European countries. In Poland it is significantly higher than Germany.

 

[Kitty]

My theory is that maybe socio-economic status also correlates with how often people share food and drinks with each other, including with their kids.

It often affects how closely people live together too. In poorer communities there tend to be more people living in smaller homes, sharing bedrooms etc.

Wealthier people may spend less time caring for young children because they use a creche to enable both parents to work, have childcare at home so they can socialise, or employ a live-in au pair.