WHO’s new guidelines on contact tracing, quarantine come out amid Omicron circulation

In light of the high levels of circulation of SARS-CoV-2, particularly the Omicron type, the World Health Organization (WHO) suggested revised criteria for patient testing and isolation on Thursday.

The health body said that quarantine duration for people exposed to the coronavirus can now be shortened, saying those who test negative can now end quarantine after seven days instead of 14 previously.

Where testing to shorten quarantine is not possible, quarantine may be ended after day 10 without testing if the contact presents no symptoms, the agency said in its new interim guidance.

It informed that the post-quarantine transmission risk for 10 days of quarantine (based on pre-Omicron data) is estimated to be around 1%, with an upper limit of about 10%.

It also stated that recently vaccinated contacts of patients can be considered as a lower priority.

But beyond approximately 90 days of vaccination, due to waning protection against infection after the primary series and limited follow-up data for booster doses, the contacts should be considered the same as unvaccinated contacts.

For Covid-19 patients, it said that countries may consider shortening the quarantine period to seven days with the addition of a PCR or Ag-RDT administered by qualified personnel. “WHO does not at this time recommend self-administered tests to shorten quarantine.”