The state of Idaho has some of the lowest prevalence of sexually transmitted diseases and infections among all the states, ranking relatively low nationally for chlamydia, gonorrhea, and primary and secondary syphilis. But before everyone in Idaho begins celebrating, examining the national picture of STDs isn’t all good news for our state. While Idaho does currently have some of the lowest rates in the country, STDs are becoming more common in Idaho, with some rates climbing dramatically in recent years.

Idaho isn’t alone, though, as the entire U.S. has seen STD rates rise for the past few years, according to the federal Centers for Disease Control and Prevention.

What sexually transmitted diseases are the most common here in Idaho, where in the state are they most prevalent, and how have rates gone up (or down) over the past few years? To get a better picture of how common these infections are here in Idaho, we’ll examine data from the CDC.

Chlamydia Rates in Idaho

About 6,200 people in Idaho were diagnosed with chlamydia in 2017, which gives the state a population-adjusted rate of 368.4 per 100,000, which is the seventh-lowest rate among the 50 states. Not only is Idaho’s rate about half that of nation-leading Alaska, it’s also significantly lower than the overall U.S. rate.

Chlamydia infections per 100,000 people

Highest
Alaska 799.8
Louisiana 742.4
Mississippi 708.7
South Carolina 649.8
New Mexico 645
Georgia 623.7
Alabama 615.5
North Carolina 612.2
New York 591.6
Illinois 589.9
Total 528.8
Lowest
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

Idaho may have a low chlamydia rate today, but if conditions continue as they are, that position may not last long. The chlamydia rate in Idaho has climbed by nearly 30% since 2012.

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

2012 285.1
2013 336.7
2014 333
2015 340.3
2016 356.3
2017 368.4

Only two Western states appear in the top 10 for chlamydia rates, and Idaho ranks as the state with the third-lowest rate in the region. Idaho’s rate is about 14% higher than the Western state with the lowest rate, Utah.

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

Alaska 799.8
New Mexico 645
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 Idaho

Idaho has the fourth-lowest prevalence of gonorrhea among the states, and the rate is only about a third what the overall U.S. rate is. Additionally, Idaho’s gonorrhea rate is more than 80% lower than that of Mississippi, the state with the highest gonorrhea rate.

Gonorrhea infections per 100,000 people

Highest
Mississippi 310
Alaska 295.1
Louisiana 256.7
South Carolina 254.4
Alabama 245.7
Oklahoma 231.4
Arkansas 223.5
North Carolina 220.9
Georgia 217.5
Ohio 216.3
Total 171.9
Lowest
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

Gonorrhea has exploded over the past several years in Idaho. It’s gone up every year since at least 2013, and between 2012 and 2017, the rate surged by more than 450%.

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

2012 10.5
2013 13.1
2014 27.1
2015 28.5
2016 38.4
2017 58.6

Idaho is at the bottom of the Weste, a region that counts just one state among the 10 highest nationally.

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

Alaska 295.1
New Mexico 214
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 Idaho

Idaho’s population-adjusted rate of primary and secondary syphilis is the 11th-lowest in the country, about 60% lower than the overall rate for the United States. In addition to falling far below the national rate, Idaho’s syphilis prevalence is over 80% lower than the level recorded in Nevada, the state with the highest syphilis rate.

Primary and secondary syphilis infections per 100,000 people

Highest
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
Total 9.5
Lowest
Idaho 3.8
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
Wyoming 0.7

Idaho’s syphilis rate has varied widely over the past few years, but it’s risen more than 440% since 2014.

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

2012 1.6
2013 0.9
2014 0.7
2015 3.4
2016 3
2017 3.8

Three Western states are among the 10 states with the highest syphilis rates, and Idaho has the third-lowest rate in the region.

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

Nevada 19.7
California 17.1
Arizona 13.1
New Mexico 9.2
Washington 9.2
Oregon 8.6
Alaska 7.6
Hawaii 6.6
Colorado 5.2
Montana 4.6
Idaho 3.8
Utah 3.7
Wyoming 0.7

HIV & Other STD Rates in Idaho

HIV

Just under 50 people were newly diagnosed with HIV in Idaho in 2017, putting the state’s population-adjusted rate at just 2.7 per 100,000 people, the fourth-lowest rate in the nation. In addition to having a relatively low rate of HIV, the state recorded a modest 4% decline in the rate between 2016 and 2017. See best HIV test options.

Hepatitis B & C

In Idaho, acute infections of both hepatitis B and hepatitis C are less common than in the U.S. overall — and mostly falling. Hep B cases occur in Idaho at a rate that’s about 60% lower than the U.S. rate and reflects a 20% decline since 2015. Hep C cases occur at a similar rate to hep B cases, with Idaho’s rate being about 60% lower than the U.S. rate, though the hep C rate has varied widely in recent years. See best hepatitis test options.

HPV

Cases of cancers caused by human papillomavirus, or HPV, are slightly less common in Idaho than in the nation as a whole. Idaho’s population-adjusted HPV cancer rate is 11.3 per 100,000, lower than the national median of 11.7 per 100,000. HPV-linked cancers are considered a primary indicator of untreated HPV, since the virus causes a majority of several types of cancers, including cervical, anal and penile cancers. See best HPV test options.

STDs in Idaho Cities & Counties

Idaho boasts some of the lowest rates of sexually transmitted diseases in the U.S., but not every area of the state can say the same.

Chlamydia

The metro areas of Pocatello and Boise account for more than half of all chlamydia cases in Idaho.

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

Elmore 525.6
Twin Falls 460.1
Nez Perce 457
Lewis 448.7
Canyon 447.3
Power 431.5
Jerome 425.2
Bannock 425.1
Ada 420.1
Shoshone 370

Gonorrhea

Nearly 60% of gonorrhea infections occur in Boise.

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

Lewis 132
Nez Perce 94.9
Camas 93.8
Ada 75.1
Lincoln 56.6
Twin Falls 54.6
Clearwater 47.1
Oneida 46.7
Butte 40
Jerome 35.1

Primary and secondary syphilis

Boise accounts for almost 2 in 3 syphilis cases that occur in Idaho.

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

Gooding 6.5
Kootenai 5.3
Canyon 4.8
Ada 4.6
Blaine 4.6
Jerome 4.4
Payette 4.4
Elmore 3.9
Bonneville 3.6
Latah 2.6

Conclusion

Sexually transmitted diseases are currently less common in Idaho than in many other states and in the nation as a whole. But if trends continue in the direction they’re going now, that could all change. Most STDs are becoming more common in Idaho, and this trend is reflected across the nation. But did you know that almost all sexually active people will contract at least one STD in their lifetime? STDs are very common, but they’re entirely avoidable through testing, treatment and prevention.

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.