Back to the research summary grind. First up, a study on cross-reactivity of antibodies among coronavirus strains. (Medrxiv Paper) All coronavirus proteins were tested for antibody reactivity. Antibodies in the blood to coronavirus strains were found in 75% of people. People who had been infected with CV-19 had some unique antibodies that were effective against some seasonal coronaviruses.
This study assessed antibody presence in children aged 2 to 15 in the UK. (Medrxiv Paper) 992 children were included in the study, 68, or around 7%, were positive and 50% of those had been asymptomatic. Most children acquired their infections in the household. None required hospitalization.
This paper reassessed social distancing guidelines in terms of not just distance but time, based on modeling of the airflow interaction between individuals. (Medrxiv Study) The authors suggest that current guidelines be revisited and a time limit added, so we can all carry a stopwatch around. Alternatively, we can have a sliding scale. If you are spending a minute or less in someone’s presence, 6 feet is good. At five minutes, stay 15 feet apart. Want to spend 15 minutes together, shout at each from down the block. Half an hour or more, use a long-distance call.
The immune response of asymptomatic individuals is of interest. Researchers examined 43 asymptomatic but positive individuals and 52 heavily exposed but not antibody positive people from a ski resort in Austria that was a hotspot for the European outbreak. (Medrxiv Paper) There was a difference in inflammatory gene product expression among those who had been infected and had mild disease, but none in this group of asymptomatic persons.
This study examined viral load dynamics in the nasal passages of infected children. (Medrxiv Paper) Ten symptomatic children were compared to 7 asymptomatic ones. The asymptomatic children had lower viral loads. In fact the average cycle number for the asymptomatic children was over 36, indicative of very low virus numbers and likely non-infectiousness. The peak viral load was about two to three days after diagnosis.
This paper discusses the antibody response among patients in Iceland. (NEJM Article) They found that antibody response persisted at a high level for at least four months. Based on prevalence estimates, they believed the case fatality rate was .3%. Antibody response appeared higher in persons who had been hospitalized. Household transmission was the most common source for acquiring the virus. Multiple assays were used, a side note is that there was variability in performance of those assays.