Two weeks after receiving the first dose of the vaccine for Sars-CoV-2 (the name of the virus causing COVID-19), I tested positive for the virus. This was probably not because of the vaccine but because I was infected with the virus. Remember, vaccines are not 100% effective, and they can take about 4 weeks to begin to have an effect in most cases. Instead of only sending off a sample to a lab which can take a few days, in my workplace, we use a lateral flow test, which gives a quick result (within 30 minutes). Here we will go through the test and how it works.