received a 3rd and accidental 4th booster shot of your COVID vaccine; received a 3rd and accidental 4th booster shot of your COVID vaccine; local injection site soreness; feeling more tired than usual; This is a spontaneous report from a contactable pharmacist. An 80-years-old male patient received bnt162b2 (BNT162B2, PFIZER-BIONTECH COVID-19 VACCINE, Solution for injection), dose 3 via an unspecified route of administration on an unspecified date (Batch/Lot number and Expiry date was not reported) as DOSE 3, SINGLE, dose 4 via an unspecified route of administration on an unspecified date (Batch/Lot number and Expiry date was not reported) as DOSE 4, SINGLE for covid-19 immunisation. Medical history included: diabetes mellitus from an unknown date and unknown if ongoing , liver cancer from 17Sep2021 to an unknown date Currently on target therapy cabozantinib 40mg , hepatitis b from 17Sep2021 to an unknown date entecavir 0.5 mg for his hepatitis B. Concomitant medications included cabozantinib 40mg and entecavir 0.5 mg .The patient previously received bnt162b2 (BNT162B2, PFIZER-BIONTECH COVID-19 VACCINE, Solution for injection), dose 1 via an unspecified route of administration on an unspecified date (Batch/Lot number and Expiry date was not reported) and dose 2 via an unspecified route of administration for COVID-19 immunisation. It was reported that a 3rd and accidental 4th booster shot of your COVID vaccine within 5 days apart of each other. Past medical history includes diabetes and liver cancer (currently on target therapy cabozantinib 40mg and entecavir 0.5mg for his hepatitis B). It occurred on 17Sep2021. Besides local injection site soreness and feeling more tired than usual, no other adverse reaction has been experienced yet. It was reported that there is currently no information on potential side effects of receiving a 4th dose of the vaccine in general or for receiving it so closely to the 3rd dose itself. Offer the information from administration of a dose larger than 30 mcg as below. Attempt to transfer to speak with DSU regarding this incident and the side effects that have been experienced. Refer to HCP for evaluation and treatment of any adverse effects. In a Phase I/II study of COVID-19 mRNA vaccines in adults, different strength doses of COVID- 19 mRNA Vaccine BNT162b2 were given. This means that some people in the trials have already received higher doses of a similar vaccine (BNT162b1) than the currently recommended dose. The trial showed that although a stronger dose (100 micrograms) was not harmful, the recipients experienced more local reactions with very painful arms being reported. Participants who received 58 micrograms of COVID-19 mRNA Vaccine [the product currently marketed as Pfizer-BioNTech COVID-19 Vaccine] in clinical trials did not report an increase in reactogenicity or adverse events. If a person is given more than the recommended dose, they should be monitored and treated for any symptoms as required. They should be reassured that this is not harmful but that they may be more likely to experience pain in their injected arm. The clinical outcome of the events was unknown.  The lot number for the vaccine, [BNT162B2], was not provided and will be requested during follow up.