The United Kingdom has expanded the official list of COVID-19 symptoms to include nine new symptoms, more than two years since the pandemic began. Monday’s updated guidance from the U.K. Health Security Agency now lists symptoms including a sore throat, muscle aches or pains, and diarrhea. Others listed include shortness of breath, unexplained tiredness or a lack of energy, loss of appetite, feeling or being sick, a headache that is “unusual” or longer-lasting than usual, and a stuffy or runny nose. Previously, symptoms included a fever, a new and persistent cough, and a loss or change in taste or smell. The Health Security Agency also noted that symptoms of COVID-19 are similar to those of other respiratory infections, and states that it is impossible for individuals to establish if they have COVID-19, flu, or another respiratory infection based on their symptoms alone. However, the decision to expand the list of symptoms from three to 12 came just days after free testing for coronavirus …