Onchee Yu, MS

“I'm pleased that my work is having a national impact by making vaccines, drugs, and medical devices even more effective and safe.”

Onchee Yu, MS

Senior Biostatistician, Kaiser Permanente Washington Health Research Institute


Onchee Yu, MS, is a biostatistician who has contributed her extensive experience in statistical applications to studies ranging from breast cancer screening and prevention to pharmacoepidemiology to vaccine safety and effectiveness. Ms. Yu has been a key member of KPWHRI's immunization research program for almost 15 years. Her work focuses on accurately measuring vaccine effectiveness, side effects, and safety. She has studied the influenza vaccine in general populations, the pneumococcal vaccine in older people, and the diphtheria-tetanus-pertussis (DTaP) vaccine in children. With KPWHRI collaborators Jennifer Nelson, PhD and Andrea Cook, PhD, Ms. Yu works on the Vaccine Safety Datalink and Mini-Sentinel projects that are developing and improving statistical methods for monitoring the safety of vaccines and drugs already on the market.

Much of Ms. Yu's recent research is in pharmacoepidemiology, which is studying how drugs are used in a population and their impact on public health. She is an expert in statistical analysis in a complex, clinically important area—determining if taking medicine for one condition affects risk of other illnesses. For example, Ms. Yu has coauthored studies on whether taking medications for heart disease or using antibiotics affects risk of breast cancer recurrence. She has evaluated how different classes of medication affect outcomes such as dementia.

Ms. Yu is a member of the American Statistical Association. Her methodological expertise includes classification and regression tree analysis and survival analysis.

Research interests and experience

  • Biostatistics

    Survival analysis; classification and regression tree analysis

  • Vaccines & Infectious Diseases

    Biostatistics; vaccine safety and efficacy; post-marketing vaccine safety study design and analysis

  • Medication Use & Patient Safety

    Biostatistics; medication use and cancer outcomes; medication use and dementia outcomes; post-marketing drug and vaccine safety study design and analysis; safety signal detection methods

Recent publications

Calip GS, Yu O, Boudreau DM, Shao H, Oratz R, Richardson SB, Gold HT. Diabetes and differences in detection of incident invasive breast cancer. Cancer Causes Control. 2019;30(5):435-441. doi: 10.1007/s10552-019-01166-2. Epub 2019 Apr 4. PubMed

Boudreau DM, Chen L, Yu O, Bowles EJA, Chubak J. Risk of second breast cancer events with chronic opioid use in breast cancer survivors. Pharmacoepidemiol Drug Saf. 2019 Apr 3. doi: 10.1002/pds.4779. [Epub ahead of print]. PubMed

Yu O, Reed SD, Schulze-Rath R, Grafton J, Hansen K, Scholes D. Identification of incident uterine fibroids using electronic medical record data. EGEMS (Wash DC). 2019;7(1):5. doi: 10.5334/egems.264. PubMed

Bowles EJA, Yu O, Ziebell R, Chen L, Boudreau DM, Ritzwoller DP, Hubbard RA, Boggs JM, Burnett-Hartman AN, Sterrett A, Fujii M, Chubak J. Cardiovascular medication use and risks of colon cancer recurrences and additional cancer events: a cohort study. BMC Cancer. 2019;19(1):270. doi: 10.1186/s12885-019-5493-8. PubMed


latest News

How should we screen for gestational diabetes?

In our learning health system, we discovered that a new screening approach had increased diagnoses without improving overall outcomes. So remarkably, we switched back.

Read it in Healthy Findings.

healthy findings blog

Patients power SIMBA research on breast cancer, mammograms, breast MRIs

A new video shows how patient engagement takes center stage in Dr. Karen Wernli’s study of breast cancer imaging for women who’ve had the disease before.

Read it in Healthy Findings.

news release

Higher dementia risk linked to more use of common drugs

Jan. 26, 2015Link persists in University of Washington / Group Health study in JAMA Internal Medicine.