GENEVA, Dec 30, 2021 (BSS/AFP) - The World Health Organization said on
Wednesday that slashing the mandatory isolation period for people with Covid-
19 was a trade-off between controlling transmission and keeping economies up
and running.

  Spain said it would shorten the quarantine for positive cases from 10 to
seven days, after US health authorities on Monday halved the recommended
isolation time for people with asymptomatic infections from 10 to five days.

  The WHO said governments were struggling to find the right balance,
following an 11 percent surge in cases around the world last week as the
Omicron variant spreads.

  "If people shorten the quarantine period, there will be a small number of
cases that will develop disease and potentially go on to transmit, because
they have been let out of quarantine earlier," WHO emergencies director
Michael Ryan told a news conference.

  "But that will be a relatively small number, and a lot of people who won't
transmit will also be released from that quarantine.

  "So it is a trade-off between the science and being absolutely perfect in
what you try to do, but then having the minimal disruption that you can
possibly have to your economy and society -- and governments are struggling
to find that balance."

  The WHO's guidelines on quarantine are, for symptomatic patients, 10 days
after symptom onset, plus at least three additional days without symptoms;
and for asymptomatic cases, 10 days after a positive test.

  Ryan said the average incubation period so far has been around five or six
days -- but there was a range.

  The likelihood of someone developing symptoms after five, six or seven days
goes down exponentially, he explained, adding that it was then for
governments to make the judgement call on when to allow people out of
isolation.

  "There is some data to suggest that the incubation period for Omicron may
be shorter, but there will still be a very wide range," he said, stressing
that this was based on very limited studies.

  "It would be advisable at this point if we don't see huge shifts, huge
moves in reducing control measures for Covid-19 purely on the basis of
initial or preliminary studies."