New Hampshire ranks among the states with the lowest rates when it comes to how common sexually transmitted diseases are in the state. Ranking among the bottom in HIV, chlamydia, syphilis and gonorrhea, many different STDs are much less common in New Hampshire than the U.S. overall. But a disturbing trend happening nationally is also having an impact here. In fact, the U.S. has seen rates of several STDs rise for four straight years, and in New Hampshire, most rates are on the uptick.

Which sexually transmitted diseases and infections are most common here in New Hampshire, how does the state compare to others in the area, how have rates of certain diseases changed over time, and which areas of the state are STD hotspots? To understand all this, we’ll examine data published by the federal Centers for Disease Control and Prevention.

Chlamydia Rates in New Hampshire

New Hampshire’s population-adjusted rate of chlamydia is the fourth-lowest in the United States. The state’s rate is more than one-third lower than the overall U.S. rate and is less than half the rate of the leading state, Alaska.

Chlamydia infections per 100,000 people

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
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

Chlamydia rates have varied widely in recent years, but between 2015 and 2017, the rate of chlamydia in New Hampshire rose by 42.1%.

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

2012 232.6
2013 235.7
2014 270.3
2015 232.6
2016 260.6
2017 330.5

Only one Northeastern state, New York, ranks among the 10 states with the highest rates of chlamydia, and New Hampshire’s rate is the second-lowest in the region, though it’s about 12% higher than the rate in Vermont, which is the region’s lowest.

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

New York 591.6
Rhode Island 500
Connecticut 496.3
Pennsylvania 441.5
Massachusetts 425.7
New Jersey 392
Maine 342.1
New Hampshire 330.5
Vermont 297.5

Gonorrhea Rates in New Hampshire

New Hampshire’s population-adjusted rate of gonorrhea infections is just 38.4 per 100,000, the second-lowest rate in the U.S. The overall U.S. rate is more than four times higher, and Mississippi, the state that leads the nation, has a rate more than 700% higher than New Hampshire’s.

Gonorrhea infections per 100,000 people

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
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

New Hampshire saw a modest increase of the gonorrhea rate between 2016 and 2017, but the rate has surged in recent years, climbing more than 245% since 2012.

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

2012 11.1
2013 9.1
2014 17
2015 18.4
2016 34.3
2017 38.4

No Northeastern states are among the 10 states with the highest gonorrhea rates, and New York is the only state in the region with a rate that exceeds the national level. New Hampshire’s rate is just over Vermont’s.

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

New York 172.7
Pennsylvania 119.2
Connecticut 109.4
Massachusetts 106.5
New Jersey 105.5
Rhode Island 102.9
Maine 46.6
New Hampshire 38.4
Vermont 32.5

Syphilis Rates in New Hampshire

New Hampshire boasts the seventh-lowest rate of primary and secondary syphilis infections among all states, and New Hampshire’s rate is six times lower than that of nation-leading Nevada and is only about one-third the national 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
Total 9.5
South Dakota 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

New Hampshire’s syphilis rate has remained relatively steady, though it’s clearly on an upward trend. The rate has gone up by nearly 20% since 2012.

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

2012 2.7
2013 2.1
2014 2.7
2015 3
2016 3
2017 3.2

New York is the only Northeastern state with a syphilis rate among the nation’s top 10, and New Hampshire has the third-lowest rate in the region.

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

New York 11.9
Massachusetts 7.9
Rhode Island 6.7
Pennsylvania 6.2
New Jersey 5.6
Maine 4.9
New Hampshire 3.2
Connecticut 3.1
Vermont 2.1

HIV & Other STD Rates in New Hampshire


Nearly three dozen people were newly diagnosed with HIV in New Hampshire in 2017, giving the state a population-adjusted rate of just 2.5 per 100,000, third-lowest in the U.S. Not only is the rate low, but the 2017 rate represents a decline of 17% from 2016. See also HIV test options.

Hepatitis B & C

Acute infections of hepatitis B have all but been eliminated in the state of New Hampshire with the rate falling from an already-low 0.3 per 100,000 to a statistically insignificant number. That compares with a national rate of 1 per 100,000 people. Information on acute hep C cases in New Hampshire is unavailable, but the national rate for that viral infection is also about 1 per 100,000. See also hepatitis test options.


Cancers caused by human papillomavirus (HPV) occur at a slightly lower rate in New Hampshire than in the average state. The population-adjusted HPV cancer rate in New Hampshire is about 11.4 per 100,000, compared to the U.S. median of 11.7 per 100,000. Measuring cancers caused by HPV is a good way of understanding how commonly HPV goes untreated, as several types of cancer, including penile, anal and cervical, are primarily caused by HPV. See also HPV test options.

STDs in New Hampshire Cities & Counties

While New Hampshire has low rates of most sexually transmitted diseases, some areas of the state have much higher rates than others, and several cities and metro areas in the state draw a larger proportion of cases.


The Manchester-Nashua area accounted for more than 1 in 3 chlamydia cases in the state, and the two New Hampshire counties in the Boston-Cambridge metro area added another 30%.

New Hampshire counties by chlamydia infection rate (cases per 100,000 people)

Strafford 346.1
Hillsborough 307.9
Belknap 242.4
Cheshire 242.4
Merrimack 234.5
Sullivan 223.4
Grafton 220.6
Rockingham 218
Coos 205
Carroll 175.5


More than 1 in 2 gonorrhea cases in New Hampshire occur in the Manchester-Nashua area, while the Boston counties added another 22%.

New Hampshire counties by gonorrhea infection rate (cases per 100,000 people)

Hillsborough 60.7
Merrimack 29.1
Strafford 27.6
Cheshire 26.3
Rockingham 21.9
Grafton 21.3
Coos 19.2
Sullivan 18.6
Belknap 18.1
Carroll 2.1

Primary and secondary syphilis

Virtually all of the syphilis cases in New Hampshire were diagnosed in people living in Concord, Boston or Manchester-Nashua.

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

Strafford 5.5
Hillsborough 3.9
Grafton 3.4
Rockingham 3.3
Coos 3.2
Merrimack 2
Cheshire 0
Sullivan 0
Belknap 0
Carroll 0


While there’s no doubt that New Hampshire’s relatively low STD rates are something to celebrate, that doesn’t mean it’s OK to be complacent. Our examination of the STD data shows that while the state does currently have low STD prevalence, the numbers are moving in the wrong direction. While many people may feel embarrassed to get tested for STDs, the truth is that’s one of the best ways to keep STD rates low. After all, most people who pass along STDs are not aware they are infected, and that’s because most people who have them don’t know it. But it’s also true that most people who are sexually active will contract at least one sexually transmitted disease, so there is no reason for anybody to feel embarrassed about learning their STD status.

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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