Human health and medicine

Sinovac live attenuated varicella vaccine

Sinovac live attenuated varicella vaccine (VarV), made by Sinovac (Dalian) from the Oka strain in the SV-1 human diploid cell line; WHO-prequalified 3 November 2022 as the first Chinese varicella vaccine, non-inferior to VARIVAX in phase III trials.

Sinsavac

SinSaVac (СинСаВак) is a live attenuated yellow fever vaccine, strain 17D, made by Russia's Chumakov Federal Scientific Center; WHO prequalified 14 October 2022, 10-dose vial, subcutaneous 0.5 mL dose.

Sintilimab

Sintilimab (信迪利单抗, Tyvyt, IBI308) is an anti-PD-1 monoclonal antibody by Innovent Biologics and Eli Lilly, first approved in China in December 2018 for Hodgkin lymphoma, with seven reimbursed indications and a 2022 FDA ODAC rejection.

Sinus (anatomy)

In anatomy, a sinus is an air-filled cavity within a bone or tissue, most often one of the four paired paranasal sinuses around the nose, which all drain into it.

Sinus bradycardia

Sinus bradycardia, also called sinus bradyarrhythmia, is a normal-rhythm heartbeat slower than 60 beats per minute, often harmless and seen in athletes and during sleep.

Sinus floor augmentation

Sinus floor augmentation, also called maxillary sinus floor augmentation, is a dental surgical procedure that lifts the sinus floor and adds bone graft to anchor implants in the upper jaw.

Sinus lift

A sinus lift, or maxillary sinus floor augmentation, is surgery that raises the sinus floor and adds bone so dental implants can anchor in the upper jaw.

Sinus node dysfunction

Sinus node dysfunction, formerly sick sinus syndrome, is impaired sinoatrial node impulse generation or conduction causing bradycardia, pauses, or chronotropic incompetence; treated with dual-chamber pacemakers per DANPACE and MOST trial evidence.

Sinus node reentrant tachycardia

Sinus node reentrant tachycardia (SNRT, SANRT, sinoatrial reentry) is a rare paroxysmal focal atrial tachycardia from microreentry in the sinus node, with sinus-like P waves, 100-150 bpm, EPS diagnosis, and ablation when drugs fail.

Oct 20, 2026

Sinus pause

Sinus pause (sinus arrest): transient failure of the sinoatrial node to discharge, seen on ECG as absent P waves; pauses over 2-3 seconds, distinguished from SA exit block by a non-multiple P-P interval.

Sinus rhythm

Sinus rhythm is the normal heart rhythm initiated by the sinoatrial node, the heart's natural pacemaker, at a rate of 60 to 100 beats per minute.

Sinus tachycardia

Sinus tachycardia: a regular heart rhythm from the sinoatrial node at over 100 bpm, usually an appropriate response to exercise, fever, or stress; also covers inappropriate sinus tachycardia (IST), a diagnosis of exclusion defined by resting HR >100 bpm.

SINUS-24 trial

SINUS-24 (LIBERTY NP SINUS-24, NCT02912468): phase 3 trial of dupilumab 300 mg every 2 weeks versus placebo for 24 weeks in 276 adults with severe CRSwNP; significantly improved nasal polyp score and congestion.

SINUS-52 trial

SINUS-52 (LIBERTY NP SINUS-52, NCT02898454), a 52-week phase 3 trial of dupilumab 300 mg in 448 adults with severe CRSwNP, met co-primary nasal polyp score and congestion endpoints versus placebo.

Sinusitis

Sinusitis (rhinosinusitis) is inflammation of the sinus lining, usually viral. Key facts: acute under 4 weeks, chronic over 12 weeks; ABRS diagnosed at 10 days without improvement or double worsening; amoxicillin 5-7 days first line.

Sinusotomy

Sinusotomy is the surgical opening of a paranasal sinus, such as the maxillary, ethmoid, frontal, or sphenoid, now usually done endoscopically to restore drainage and ventilation in chronic rhinosinusitis.

Oct 20, 2026

Siponimod

Siponimod (Mayzent), an oral S1P1/S1P5 receptor modulator approved in 2019 for relapsing forms of multiple sclerosis, reduces disability progression in active secondary progressive MS per the phase 3 EXPAND trial.

SIR model

The SIR model, or SIR epidemic model, is a compartmental model in mathematical epidemiology that divides a population into susceptible, infected, and recovered individuals to predict how disease spreads.

Siriraj Hospital

Siriraj Hospital (โรงพยาบาลศิริราช), Bangkok Noi, Thailand's first modern hospital, opened 26 April 1888 by King Chulalongkorn; teaching hospital of Mahidol University's Faculty of Medicine, with private wing SiPH, about 2,044 beds, and the Bangpho Medical Hub expansion.

Sirolimus

Sirolimus (rapamycin, Rapamune) is an mTOR-inhibitor immunosuppressant from Streptomyces hygroscopicus, discovered in Easter Island soil in the 1960s, approved by the FDA in 1999 for kidney transplant rejection prophylaxis and for lymphangioleiomyomatosis.