Sunday, 27 October 2013

MERS-CoV antibodies not found in children in 2010-11 or adults from 2012

Gierer and colleagues from the German primate center and the University of Dammam in Saudi Arabia, have presented the findings of their study of antibodies to the Middle East respiratory syndrome coronavirus (MERS-CoV).

The publication, in Emerging Infectious Diseases (ahead of print - you can find it here, at least until it's other link here starts working), measured the antibodies capable of blocking infection by MERS-CoV, called "neutralising antibodies" with a method they have described before. The assay was not validated with multiple MERS-CoV-positive patient sera, but appeared specific in the testing completed. None of the sera stopped the MERS-CoV Spike protein coated virus-like particles (VLP) from entering the Caco-2 cell line. Entry of the lentivirus/Spike hybrids was measured by enzyme activity inside the cells if infection is successful. Less or no activity if the VLP could not enter the cell because the VLP's Spike proteins were bound after pre-incubation with anti-MERS-CoV-containing patient sample. 

Patient samples from the area served by King Fahd Hospital were obtained from:

  1. Children (158 sera, 77 female, mean age 12 months) admitted to hospital with lower respiratory tract infections during 12-months form May 2010. 
  2. Adult (110 plasma samples, all males, mean age 28-years, upper limit of 52-years) blood donors 
No sera or plasma had neutralising MERS-CoV antibodies.

The authors conclude that <2.3% of children and <3.3% pod adults were seropositive though, because that accounts for the upper limit of the confidence intervals. They also note that their sampling of hospitalized children could have missed an antibody response (because it takes time to develop) if they had only just been admitted to hospital for MERS-CoV. 

Additionally, its a pretty small sample on which to be base too many conclusions when considering a virus that is spread across a 2,100,000kms2 and reportedly caused notable disease in <200 of 28,000,000 people.