Spread of SARS-CoV-2 in the Icelandic Population - NEJM

14-4-2020; DOI: 10.1056/NEJMoa2006100
By: Gudbjartsson, et al.

Aim
Determine spreading characteristics of Sars-CoV-2 in a relatively closed population

Summary

In Iceland, targeted testing (persons with symptoms or returning from endemic areas) began on 31-1-2020. In addition, on 13-3 Iceland started population screening open for all symptom-free (and quarantine free -due to travelling e.g.- residents of Iceland. They also performed screening in randomly chosen Icelanders between 20y and 70y old

9199 patients received targeted testing. 

• 13.3% positive
• In the early phase, 65% of positive patients travelled abroad. Later, this decreased to 15%. 
• 40.1% of positive patients were in contact with a known infected person increasing to 60% in later periods of the study
• 93% of positive patients reported symptoms

13090 persons in population screening

• 0.8% positive

   

  • Remained stable, indicating the quarantantine and social distancing measures were successful
• 57% of positive patients reported symptoms

2283 persons in random screening

• 0.6% positive

In any screening: elderly were more likely to be positive. 

Children under 10y old were half as susceptible for positive testing compared to adults/adolescents

More females were tested, however men had an OR of 1.66 of a positive test. 

RNA-sequencing shows different world regions have different viral haplotypes

• Later stages of the study showed a decrease of known haplotypes (from the Alps e.g.) but showed increase of infected persons who seeded infection from areas that had not been designated as high risk (UK). 

The figure shows the proportion of infections related to travel decreased whereas family infection increased over the study period.