close up of a COVID-19 spike

Volunteers vital in finding effective COVID-19 vaccine

Several vaccine candidates against SARS-CoV-2, the virus that causes COVID-19, have entered the final clinical trials required for licensure. The primary goal of the trials is to test the vaccine candidates’ effectiveness and gather further information on safety. Altogether, tens of thousands of people will be recruited to participate in the different vaccine trials. Public interest in vaccine trials has never been greater and many wonder what volunteers can expect while participating.

For the most part, the late stage trials for the different vaccine candidates are similar and differ only in minor details. The first visit is the longest and is likely to take several hours. The research team must make certain that volunteers understand the study and are voluntarily participating. Once the consent is signed, the research team questions the volunteers about their medical history to ensure that they qualify for the study. Then vital signs are obtained and a brief physical exam may be performed. Baseline blood-work is obtained and a pregnancy test is performed on women of childbearing potential. Volunteers have a nasal swab done to test for the presence of SARS-CoV-2.

Only after the medical history, physical and specimens have been collected do the volunteers receive their study injection which is either the vaccine candidate or a saline placebo (salt water). The volunteers are observed to make sure there are no adverse reactions. The research team uses the observation time to instruct the volunteers about keeping a vaccination diary.

The diaries are electronic and are either an app on a cellphone or another device. The volunteer is required to keep the diary for one or two weeks after injection. Volunteers must record their temperature each day and any symptoms they may have like muscle aches, headache and chills.

The second visit is a month after the first. It involves a blood draw and a repeat pregnancy test. Then the second injection is given and followed by an observation period. The visit is much shorter because the consent process is not repeated. Volunteers are required to make daily diary entries just like they did following the first injection.

After the first two sessions, several short visits are required for blood draws to measure response to the vaccine. Volunteers that develop symptoms that may be SARS-CoV-2 will have additional visits to test for the virus. Those with SARS-CoV-2 will be monitored, and the severity of symptoms will be recorded. Participation in the study is for about two years. The research team usually contacts the volunteers during the length of the study by telephone to see if the volunteers have developed any new health issues.

Volunteers are supplied all of the necessary equipment to participate. They are also compensated for their travel, time and effort. It’s important that people considering participating in the vaccine trials understand they may or may not receive the investigational vaccine. They may receive a placebo.

We should all thank the volunteers. Without their commitment and efforts, we would never have a licensed vaccine against SARS-CoV-2.

Vaccine Smarts is written by Sealy Institute for Vaccine Sciences faculty members Drs. Megan Berman, an associate professor of internal medicine, and Richard Rupp, a professor of pediatrics at the University of Texas Medical Branch. For questions about vaccines, email