Sunday, 28 July 2013

Human endemic coronaviruses and underlying conditions....

Human coronaviruses (HCoVs), that is, the ones that circulate all the time, not the ones that spillover from an animal host to cause havoc and mayhem, come in four flavours....

  • HCoV-229E
  • HCoV-OC43
  • HCoV-NL63
  • HCoV-HKU1
On the back of my last post, I thought I'd start looking into what HCoVs do among those with some sort of pre-existing disease or condition.

Generally speaking, the HCoVs circulate spasmodically; each peaking every couple years and then often in small numbers.
Clinical studies that include virus testing and with a focus on comorbidities seem rare as are studied focussing on older age groups using PCR to screen for an extended panel of respiratory viruses (beyond the "standard 8 or so).

Some findings below....
  1. Gaunt and colleagues noted in 2010 that 229E was over-represented among the immunosuppressed compared to other HCoVs and respiratory viruses in general. 
  2. El-Sahly and colleagues noted in 2000 that 13/16  HCoV antibody detections occurred among inpatients >35-years of age. Of those infected with an HCoV or a rhinovirus in this age band, 73% had underlying cardiopulmonary disease
  3. Cabeca and colleague noted in 2012 that of the 5/394 mostly paediatric inpatient samples POS for a HCoV, 4 (80%) had a comorbidity
  4. We noted in 2012 that in 13/61 (21.3%) HCoVs positives, chronic underlying disease or immunocompromise was noted. Most (69%) were POS for OC43
  5. Lau and colleagues noted in 2006 that among the 13/4181 samples from mostly child inpatients POS for HKU1, 8 (61.5%) had underlying diseases
  6. Garbino and colleagues noted in 2006 that among 29/540 adult bronchoalveolar lavage samples POS for an HCoV (69% male), 14 (48%) had a comorbidity
  7. Kuypers and colleagues noted in 2007 that among 66/1043 children positive only for an HCoV, were more likely to have a comorbidity than children with with coinfections
  8. Al Hajjar and colleagues noted in 2011 that among 4/489 specimens (0.8% of samples) from paediatric patient samples in the Kingdom of Saudi Arabia that were POS for NL63, all had an underlying condition.
So this snapshot of studies shows that HCoVs do not contribute to a vast number of cases, similar to the MERS-CoV to date, but that there seems, by eyeball alone, to be a bias towards illness in HCoV-POS patients with underlying conditions-age not being limited to those >50-years.

Feel free to add any papers to this list. I'm also looking for papers studying older populations.