After you receive your first vaccine, it is likely that you may feel instantly relieved about the prospect of catching the virus. In reality, your first vaccination will be a step towards producing the antibodies that you’ll need to ward off COVID-19 virus. The first dose will provide the protection up to 50% for both Moderna and Pfizer vaccines 1 to 2 weeks after receiving the dose. To achieve the full effectiveness of either Moderna or Pfizer vaccines, the second shot must be administered. The second shot will strengthen the immune response and will provide protection up to 95% 1 to 2 weeks after receiving the second dose.