Since you employ the natbib citation management package with a bibliography style that produces authoryear-style citation call-outs, I suggest you employ citation aliasing mechanism along the following lines, where I've defined "WHO" as a citation alias for an entry with key who:2021. (You're obviously free to choose a different abbreviation/acronym.) Then, just use \citetalias{who:2021} instead of \citet{who:2021}.

Note that since "World Health Organization" in an example of a "corporate" author, it's necessary to write author = {{World Health Organization}}, in order to prevent BibTeX from interpreting the author field as containing a single author with last name "Organization" and given names "World" and "Health".
\documentclass{article} % or some other suitable document class
% create a sample bib file 'on the fly':
\begin{filecontents}[overwrite]{mybib.bib}
@misc{who:2021,
author = {{World Health Organization}},
year = 2021,
title = {Covid-19},
}
\end{filecontents}
\usepackage[authoryear,round]{natbib}
\bibliographystyle{apalike}
\defcitealias{who:2021}{WHO}
% optional:
\usepackage{xcolor}
\usepackage[colorlinks,allcolors=blue]{hyperref}
\begin{document}
\noindent
According to \citet{who:2021} (hereafter: \citetalias{who:2021}), \dots
\bibliography{mybib}
\end{document}
natbiborapacite? – Mico Sep 01 '22 at 18:35