Do I really need to get my second dose of the vaccine?

Do I really need to get my second dose of the vaccine?

By Dr. Henning Ansorg, M.D., FACPHealth Officer County of Santa Barbara, Department of Public Health

If you receive a Pfizer-BioNTech or Moderna COVID-19 vaccine, you will need two shots to get the optimal protection.

It is true, that even after only one injection of the Pfizer or Moderna Vaccine, the immune system will respond and provide an initial protective shield against infection and severe disease from COVID. In order to receive the optimal and long-lasting protection, however you will need the second dose of the regimen.

The only vaccine that requires one injection only to achieve an optimal immune response is the Janssen vaccine by Johnson & Johnson.

There is one reason to not get the second dose of Pfizer or Moderna and that is, if you experienced a severe allergic reaction (anaphylaxis) after the first shot. In these instances, you MUST not receive further Pfizer or Moderna vaccines, however you are advised to get the Janssen (Johnson& Johnson) vaccine as your second dose because it does not cause anaphylaxis.

The Centers for Disease Control, (CDC) states that second vaccine doses should be administered as close to the recommended interval as possible, within 21 days for the Pfizer vaccine and 28 days for Moderna. However, if delays are unavoidable , a second dose may be given within 42 days, or six weeks without diminishing the booster effect. 

Planning for your second shot is important. If you need help scheduling your vaccination appointment for your second shot, contact the location that set up your first appointment. In Santa Barbara County, first and second-dose appointments are now being scheduled at the same time through the State’s My Turn website. You can also call 2-1-1, option 4 to schedule your second dose appointment.

At your first vaccination appointment, you should have received a vaccination card that tells you what COVID-19 vaccine you received, the date you received it, and where you received it. It is important to remember to bring this vaccination card to your second vaccination appointment.

For those who need assistance with scheduling their vaccine or would like additional information, Santa Barbara County offers an informational website at:  For those without Internet services or those requiring additional assistance, dial 2-1-1.