itemize - bullets points not showing up

Question

I cannot figure out why the bullet points are not showing up.

\documentclass{beamer}
%
% Choose how your presentation looks.
%
% For more themes, color themes and font themes, see:
% http://deic.uab.es/~iblanes/beamer_gallery/index_by_theme.html
%
\usepackage{fourier} 
\usepackage{array}
\usepackage{makecell}
\usepackage{longtable}
\usepackage{enumitem}
\usepackage{comment}

\mode<presentation>
{
  \usetheme{CambridgeUS}      % or try Darmstadt, Madrid, Warsaw, ...
  \usecolortheme{beaver} % or try albatross, beaver, crane, ...
  \usefonttheme{structuresmallcapsserif}  % or try serif, structurebold, ...
  \setbeamertemplate{navigation symbols}{}
  \setbeamertemplate{footline}[frame number]
  \setbeamercovered{transparent}
} 

\usepackage[english]{babel}
\usepackage[utf8x]{inputenc}


\title[Your Short Title]{Post-Circumcision Risk Compensation: A Systematic Review}
\author{Dana Ivanova, Njeri Kamau}
\institute{Topics in Epidemiology}
\date{15 January 2019}

\begin{document}

\begin{frame}
  \titlepage
\end{frame}

% Uncomment these lines for an automatically generated outline.
%\begin{frame}{Outline}
%  \tableofcontents
%\end{frame}


\section{Background}


\begin{frame}{sub-Saharan Africa}
    \begin{itemize}
     \item globally 35 million people are  HIV positive
     \item role of sub-Saharan Africa
    \end{itemize}