Nervous; This is a spontaneous report from a contactable consumer (patient). A male patient of an unspecified age received first dose of BNT162b2 (PFIZER BIONTECH COVID-19 mRNA VACCINE, Solution for injection, Lot number- unknown) via an unspecified route of administration as dose 1 single and second dose of BNT162b2 (PFIZER BIONTECH COVID-19 mRNA VACCINE, Solution for injection, Lot number- unknown) via an unspecified route of administration as dose 2 single for COVID-19 immunization. Medical history included rheumatoid arthritis, erectile dysfunction and immunocompromised. Concomitant medication included tofacitinib citrate (XELJANZ), aspirin [acetylsalicylic acid] (ASPIRIN 81), sildenafil citrate (VIAGRA) for erectile dysfunction. Patient stated that he had been tested for antibodies three times after receiving the two doses of the Pfizer COVID-19 vaccine. He stated that he took the antibody test, and two spike antibody tests and both came back with no antibodies. He stated that on an unspecified date, he was nervous because of the delta variant and he does not think he was protected. He stated that his doctor does not have information for him. He called the head of the immunization department, and they told him that it was up to him to make the choice on whether or not he wants to get another vaccine or not. He called a doctor and he was told to take the third shot. He stated that he was at a loss especially because he was immunocompromised because of his rheumatoid arthritis. He stated that he does not know if the booster shot is going to have the same ingredients as the two dose series, and he wanted to know what possible side effects are going to come from getting the third dose of the vaccine. He stated that if it is the same ingredients he will go an take another dose of the vaccine. He just wanted some sort of response because his doctor does not know what ingredients are going to be in the booster. He stated that the Problem is, look they know what is in the drug, not asking them to guarantee anything, what ever is in there is it the same. He stated his doctor suggests double masking. He stated that the precautions did not work if someone who was not taking precautions and get the variant and then they give it to him. He stated is there any information on getting a third shot of the dose that is already released (normal dose). In response as part of Pfizer's and BioNTech's continued efforts to stay ahead of the virus causing COVID-19 and circulating mutations, the companies provided an update on booster dosing on 09Jul2021. Please note that the use of a 3rd or booster dose is not recommended or authorized and Pfizer does not suggest the use of the vaccine in any manner other than as described in the authorized EUA Prescribing Information authorized product monograph. Initial data from the ongoing study of booster doses demonstrated a consistent tolerability profile and high neutralization titers against the wild-type virus (the naturally occurring non-mutated virus) and the Beta variant. It is thought that the effects seen against the Beta variant may also be seen in the Delta variant. We are doing studies to confirm this. Caller was informed that in review of the EUA prescribing information for the COVID-19 vaccine no information was found about the side effects and dosage of the booster vaccine. Caller was referred to his doctor. Caller wanted to know if he can be a part of the clinical trials. In response caller was given the clinical trials phone number. The outcome of the event was unknown.  Follow-up attempts are completed. No further information is expected.