Greek letters are often used as parts of scientific labels, which adds authority to the idea. The Greek-letter labelling proposed by the WHO is therefore an official attempt to provide the convenience of simple, uncontroversial monikers. ALPHA, BETA, gamma, delta. And, at least to those familiar with the alphabet concerned, the names instantly convey information about what order the variants were discovered in. Currently, there are no plans on how to label the variants after the 24 letters of the Greek alphabet are used up.
The Greek letter labelling proposed by the WHO is effective.
( z0 effective :ARG0 ( z1 label :ARG1-of ( z2 propose :ARG0 ( z3 organization :name ( z4 name :op "WHO" ) ) ) :ARG2 ( z5 letter :mod ( z6 language :name ( z7 name :op "Greek" ) ) ) ) )
(z0 / effective-04
    :ARG0 (z1 / label-01
              :ARG1-of (z2 / propose-01
                           :ARG0 (z3 / organization
                                     :name (z4 / name
                                               :op1 "WHO")))
              :ARG2 (z5 / letter
                        :mod (z6 / language
                                 :name (z7 / name
                                           :op1 "Greek")))))
The Greek letter labelling proposed by the WHO is effective .
z6 :name z7
z7 :op1 0
z5 :mod z6
z1 :ARG2 z5
z1 :ARG1-of z2
z2 :ARG0 z3
z3 :name z4
z4 :op1 1
z0 :ARG0 z1