SUSPECTED COVID-19 INFECTION; DEHYDRATION; This spontaneous report received from a consumer via other manufacturer (Pfizer Inc.) concerned a 70 year old female. The patient's height, and weight were not reported. The patient's concurrent conditions included: chronic lymphocytic leukemia (CLL), penicillin allergy, and drug allergy (narcotics), and other pre-existing medical conditions included: The patient was not pregnant at the time of vaccination.  The patient previously received covid-19 vaccine ad26.cov2.s (dose number in series 1) (suspension for injection, route of administration was not reported, batch number: 043A21A, expiry: unknown) dose was not reported, first dose, 1 total administered on 03-APR-2021;11:00 to left arm for covid-19 prophylaxis. It was unknown whether patient had any adverse events following vaccination with covid-19 vaccine ad26.cov2.s (dose number in series 1). The patient received covid-19 vaccine ad26.cov2.s (dose number in series 2) (suspension for injection, route of administration was not reported, batch number: 1822811 expiry: unknown) dose was not reported, second dose, 1 total administered on 29-OCT-2021 13:00 to left arm for covid-19 prophylaxis. Age at time of vaccination was 69 years old. Concomitant medications included guaifenesin (Mucinex), loratadine (Claritin), and midodrine. On an unspecified date, the patient had covid-19 (dose number in series 2). The patient started taking treatment with non-company suspect drug paxlovid (nirmatrelvir/ritonavir) (form of administration, route of administration and batch number were not reported, expiry: unknown) dose and frequency were not reported from 12-JAN-2023 to 16-JAN-2023 for covid-19 treatment. On 20-JAN-2023, 8 days after the first dose of paxlovid drug treatment, she had covid-19 rebound (coded as suspected covid-19 infection) and was hospitalized (date unspecified) with much worse symptoms of vomiting and dehydration (dose number in series 2).  On 24-JAN-2023 (day 12), the patient had received intravenous (IV) fluids and breathing treatment at the emergency room for events. The number of days of hospitalization was not reported and it was unspecified if the patient discharged from the hospital. On 31-JAN-2023, 19 days after the first dose of paxlovid drug treatment, she had finally tested negative for COVID-19 virus test.  On 09-FEB-2023, the patient still had symptoms of cough, congestion, bad smells, exhaustion. The action taken with covid-19 vaccine ad26.cov2.s was not applicable and with paxlovid was unknown. The patient had not recovered from suspected covid-19 infection, and the outcome of dehydration was not reported. This report was serious (Hospitalization Caused / Prolonged).; Sender's Comments: V0-20230231193-Suspected Covid 19-The event is deemed to be scientifically implausible, i.e., there is scientific evidence against a drug/event relationship; AND there is no known class effect. Therefore, this event is considered inconsistent with vaccine administration.  V0-20230231193- Dehydration- The event has a compatible/suggestive temporal relationship, is unlabeled, and has unknown scientific plausibility. There is no information on any other factors potentially associated with the event. Therefore, the WHO Causality is considered indeterminate. The company causality is considered unassessable.