When it comes to the prevalence of several different sexually transmitted diseases (STDs), Washington ranks among the states with the lowest rates. While this isn’t true of all sexually transmitted diseases and infections, the state mostly has had success in controlling rates of STDs. But that’s changing. In fact, rates of chlamydia, gonorrhea, syphilis and HIV all are on the rise, which reflects a trend that’s seen rates of most of those STDs rise for the past four years across the United States, according to the federal Centers for Disease Control and Prevention.

Which sexually transmitted diseases and infections are most common here in Washington, how have their rates changed over time, and which locales in Washington have the highest concentrations of infected individuals? To understand the picture of STDs in Washington, we’ll examine data from the CDC as well as the Washington State Department of Health.

Chlamydia Rates in Washington

Washington ranks 36th out of all 50 states with a population-adjusted chlamydia rate more than 15% lower than the overall U.S. rate.

Chlamydia infections per 100,000 people, bottom 20

Hawaii 479.5
Iowa 467
Kansas 466.2
Nebraska 450.7
Oregon 450
Minnesota 444
Washington 444
Pennsylvania 441.5
Montana 437.4
Kentucky 435.4
North Dakota 432.5
Massachusetts 425.7
New Jersey 392
Idaho 368.4
Wyoming 365.8
Maine 342.1
New Hampshire 330.5
Utah 323.7
Vermont 297.5
West Virginia 226.1
Total 528.8

Washington’s position as one of the states with the lowest rates of chlamydia could be in danger, though, as the state has seen the rate rise every year since 2012. Between 2012 and 2017, the state’s chlamydia rate has gone up by nearly 25%.

Washington chlamydia rate by year (cases per 100,000 people)

2012 356.6
2013 357.9
2014 376.4
2015 400.2
2016 435.9
2017 444

Two Western states rank in the top five nationally, and Washington is in the bottom half of the region with a rate barely lower than that of neighboring Oregon.

Chlamydia infection rate, Western region states (cases per 100,000 people)

Alaska 799.8
New Mexico 651.6
Arizona 571.8
California 557.4
Nevada 544.7
Colorado 481.3
Hawaii 479.5
Oregon 450
Washington 444
Montana 437.4
Idaho 368.4
Wyoming 365.8
Utah 323.7

 Gonorrhea Rates in Washington

Washington ranks No. 33 in the country when it comes to the prevalence of gonorrhea, and the state’s rate is more than 20% lower than the overall U.S. rate.

Gonorrhea infections per 100,000 people, bottom 20

Minnesota 142
Nebraska 139.1
Washington 137.1
Wisconsin 135
North Dakota 127.4
Oregon 121.3
Pennsylvania 119.2
Connecticut 109.4
Massachusetts 106.5
New Jersey 105.5
Rhode Island 102.9
Hawaii 95.1
Utah 81.2
Montana 75
West Virginia 70.8
Wyoming 70.4
Idaho 58.6
Maine 46.6
New Hampshire 38.4
Vermont 32.5
Total 171.9

Washington has seen the gonorrhea rate surge in recent years, nearly tripling between 2012 and 2017.

Washington gonorrhea rate by year (cases per 100,000 people)

2012 46.9
2013 62.7
2014 88.1
2015 100
2016 114
2017 137.1

Alaska is the only Western state that ranks among the top 10 for gonorrhea, and Washington sits in the middle of the region.

Gonorrhea infection rate, Western states (cases per 100,000 people)

Alaska 295.1
New Mexico 215.7
California 192
Nevada 184.9
Arizona 180.5
Colorado 151.1
Washington 137.1
Oregon 121.3
Hawaii 95.1
Utah 81.2
Montana 75
Wyoming 70.4
Idaho 58.6

Syphilis Rates in Washington

Washington ranks 14th among all the states when it comes to infections of primary and secondary syphilis, the two earliest but most infectious stages of syphilis, which can be fatal if it goes untreated. Washington’s syphilis rate is just under the overall U.S. rate.

Primary and secondary syphilis infections per 100,000 people

Nevada 19.7
California 17.1
Georgia 14.5
Louisiana 14.5
Arizona 13.1
Maryland 12.2
New York 11.9
Florida 11.6
North Carolina 10.6
Mississippi 10.4
Washington 9.2
Total 9.5
Utah 3.7
West Virginia 3.4
New Hampshire 3.2
Connecticut 3.1
Wisconsin 3
Iowa 2.7
Nebraska 2.3
Vermont 2.1
Alaska 1.8
Wyoming 0.7

Washington is poised to move up the state rankings based on the movement of the syphilis rate here in the state. The syphilis rate has increased more than 115% in Washington since 2012.

Washington primary and secondary syphilis rate by year (cases per 100,000 people)

2012 4.4
2013 4.1
2014 4.9
2015 6.2
2016 7.9
2017 9.2

Three of the 10 states with the highest syphilis rates are in the West, and Washington ranks in the top half of the region.

Primary and secondary syphilis infection rates, Westerm states (cases per 100,000 people)

Nevada 19.7
California 17.1
Arizona 13.1
New Mexico 9.3
Washington 9.2
Oregon 8.6
Hawaii 6.6
Colorado 5.2
Montana 4.6
Idaho 3.8
Utah 3.7
Alaska 1.8
Wyoming 0.7

HIV & Other STD Rates in Washington


More than 400 people were newly diagnosed with HIV in Washington in 2017. The state’s population-adjusted rate ranks Washington 31st of the 50 states, and Washington saw the HIV rate rise between 2016 and 2017, though the increase was a modest 2%. See How to Test for HIV

Hepatitis B & C

Acute infections of both hepatitis B and hepatitis C occur at lower rates in Washington than nationally, though both hepatitis virus types are becoming more common here in our state. Washington’s population-adjusted hep B infection rate is about 40% lower than the U.S. rate, but the rate increased by 20% between 2015 and 2016. Acute hep C cases are about 10% less common in Washington than the nation overall, but the rate climbed by more than 12% between 2016 and 2017. See How to Test for Hepatitis


Washington just barely ranks among the bottom half of the states when it comes to the prevalence of cancers related to human papillomavirus, or HPV. Pinpointing exactly how many people have HPV at any given time is impossible due to how incredibly common the virus is. In fact, most sexually active people will contract it at some point in their lives. But examining the frequency with which cancers caused by HPV are diagnosed can help us understand how common untreated HPV is since HPV causes a huge majority of several types of cancer, including cervical, penile and anal cancers. HPV-related cancers occur in Washington at a rate of 11.6 per 100,000, just under the national median of 11.7 per 100,000. See How to Test for HPV

STDs in Washington Cities & Counties

While Washington mostly ranks among the states with the lowest rates of STDs (with the exception of syphilis), certain areas in the state have far higher infection rates than others.


More than 1 in 2 chlamydia cases in Washington in 2017 were diagnosed in people living in the Seattle-Tacoma metro area, which had the 10th highest increase of chlamydia between 2013 and 2017.

Washington counties by chlamydia infection rate (cases per 100,000 people), top 10

Whitman 916.9
Yakima 649.4
Pierce 632.3
Franklin 572.4
Kittitas 536.6
Benton 468.2
Adams 468
Spokane 467.6
King 453.2
Cowlitz 451.4


More than two-thirds of gonorrhea infections in the state occurred in the Seattle-Tacoma area, which had the eighth-highest increase between 2013 and 2017 among all major U.S. metro areas.

Washington counties by gonorrhea infection rate (cases per 100,000 people), top 10

Pierce 206.2
King 194
Yakima 171.2
Franklin 142.8
Asotin 139.1
Spokane 138.7
Grant 121.3
Benton 111.6
Clark 108.5
Kitsap 104.4

Primary and secondary syphilis

Just under two-thirds of all syphilis infections in the state in 2017 were in individuals living in the Seattle-Tacoma metro area, which had the nation’s 15th-highest increase of the disease among all major metros.

Washington counties by primary and secondary syphilis infection rate (cases per 100,000 people)

Cowlitz 19.8
Spokane 15.6
King 15
Pierce 7.3
Clark 7
Kitsap 6.8
Snohomish 6.7


The state of Washington has rates of sexually transmitted disease and infections that are relatively low, which is good news. But, like the nation overall, Washington has seen rates of most STDs rise in recent years, including huge surges of certain infections. The truth is that almost all sexually active people will contract at least one STD at some point in their lifetimes. Unfortunately, it’s also true that the majority of people who are carrying an STD do not know they are infected. One of the best ways to make progress against the rising tide of STDs is to get tested for the infections you’re at the highest risk of having so that you can be sure you’re not passing infections along to your sexual partners.

Additional References

Note: Some states have published more recent data for chlamydia, gonorrhea, and primary and secondary syphilis. For states in which that’s the case, we have substituted the individual state data for 2018 and used that in our rankings, while other states’ rankings are based on 2017 numbers. In some cases, we assume that when the full national dataset is published by the CDC, states’ positions relative to other states will change some, though those changes are unlikely to be dramatic, since the CDC data comes from the states.


by AtHomeSTDKit

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