Editor's note: This story has been updated to add new cases and new exposure sites.

Twelve new cases of measles have been confirmed this week in Oakland County, according to the state Department of Health and Human Services. Four were confirmed Tuesday and eight other cases were announced Monday.

That brings the total number of measles cases in Michigan this year to 34. All but one are in Oakland County. Wayne County reported a single case in March.

Those who have been infected with measles in Michigan range in age from 8 months to 63 years old, the MDHHS reports. The last time the state had this many measles cases was in 1991, when 65 cases were reported.

"Most of the cases so far have been in adults," said Lynn Sutfin, a spokeswoman for the MDHHS, which highlights why it's important to know your immunization status.

More:Vaccine debate ignites as measles outbreak threatens Michigan

"If you feel you have been exposed to measles and are not protected, you should watch for symptoms and self-isolate if symptoms begin," Sutfin said. "If symptoms persist and you potentially develop a rash, contact your health care provider and consult with them. Measles is extremely contagious so if you feel you may have measles you should isolate yourself from other individuals until you can confirm if you have measles or not."

Health officials say two doses of the measles, mumps and rubella (MMR) vaccine offers the best protection from the virus, which is transmitted through person-to-person contact or through droplets in the air when an infected person coughs or sneezes. The virus can live for up to two hours in the air where the infected person was present.

Although the vaccine provides the best protection, Sutfin said at least three of the people who have contracted the virus in Michigan had documentation of the two recommended doses of the MMR vaccine. At least 27 had incomplete or unknown MMR vaccination status. .

Even if an adult remembers getting two doses of the MMR vaccine, if there isn't a record of those immunizations, the state has to report that person as having an incomplete or unverified vaccination status, she said.

Macomb County adds bank to measles exposure sites

Proving the immunization status of anyone born prior to 1998 can be tricky, Sutfin said. That's when the Michigan Care Improvement Registry (MCIR) immunization database began tracking the vaccines given to children in the state. It wasn't until 2006 that adult immunizations were added to the database.

"Many vaccine records were lost," Sutfin said. "Some adults are just old enough that they may have received all the routine vaccines when they were kids but it may not have included measles because it was newer compared to DTP (diphtheria, pertussis and tetanus) or polio."

Since the outbreak began, Sutfin said 1,930 people in Oakland County have received the MMR vaccine, which can work to prevent measles if administered within 72 hours after exposure, she said.

Those most at risk include those who don't know their immunization status, pregnant women and those who have a weakened immune system because of illness and diseases like HIV, malnutrition and/or medications.

Michigan's outbreak comes as measles cases are also surging nationally. So far this year, 387 cases of measles have been confirmed in 15 states.

Sometimes, Sutfin said, even people who have had the two recommended doses of MMR vaccine can develop the disease.

"Many things could contribute to vaccine failure. If an individual was immune-compromised at the time the vaccine was administered or had something going on with their immune system that could have prevented them from responding to the vaccine," Sutfin said. "It could also be the way the vaccine was handled. If not stored properly, the viability of the vaccine could be impacted. Finally, everybody’s immunize system is different and for some reason some individuals do not respond to the vaccine."

Michigan measles exposure sites

If you're unsure of your vaccination status or are concerned about whether you have immunity to measles, health officials urge you to talk to your doctor, especially if you have been to one of the following exposure sites during these times and dates:

April 1

Yeshivas Darchei Torah School, 21550 West 12 Mile Road, Southfield, 9 a.m. – 2 p.m.

March 29

Congregation B'Nai Israel: 15400 W. Ten Mile Road, Oak Park, 5:30-8 p.m.

Bais Haknesses Hagrah, 14561 W. Lincoln Blvd., Oak Park, 7-10 a.m.

Beaumont Medical Building, first Floor: 3535 W. Thirteen Mile Road, Royal Oak, 2:30-5 p.m.

Yeshivas Darchei Torah School, 21550 W. Twelve Mile Road, Southfield, 9 a.m.-7 p.m.

March 28

Bais Haknesses Hagrah: 14561 W. Lincoln Blvd., Oak Park, 7-10 a.m.

Yeshivas Darchei Torah School: 21550 W. Twelve Mile Road, Southfield, 9 a.m.-7 p.m.

Congregation B'Nai Israel: 15400 W. Ten Mile Road, Oak Park, 5:30-8 p.m.

March 23

Yeshiva Gedolah of Greater Detroit: 24600 Greenfield Road, Oak Park, 7- 9 p.m.

Congregation Shomrey Emunah: 25451 Southfield Road, Southfield, 7:30-10 p.m.

Bais Chabad Synagogue 15401 W. Ten Mile Road, Oak Park, MI 9:30 a.m.-1:30 p.m.

March 22

Aldi: 26300 Greenfield Rd, Oak Park, 1:15-4 p.m.

Yeshiva Gedolah of Greater Detroit: 24600 Greenfield Road, Oak Park, 7-9:30 p.m.

Berkley Urgent Care: 3270 Greenfield Road, Berkley, Noon-4 p.m.

Congregation Shomrey Emunah: 25451 Southfield Road, Southfield, 7:30-10 p.m.

One Stop Kosher Food Market: 25155 Greenfield Road, Southfield, Oak Park, 1:45-4:30 p.m.

March 21

Beaumont Hospital, Royal Oak - Emergency Department: 3601 W. Thirteen Mile Road, Royal Oak, 10:30 a.m.-6 p.m.

Mapleview Liquor Store: 6084 Maple Road, West Bloomfield Township, 11 a.m.- 2 p.m.

Yeshiva Gedolah of Greater Detroit: 24600 Greenfield Road, Oak Park, 8:40-11 a.m.

Dovid ben Nuchim, 14800 Lincoln St., Oak Park, all day

Congregation Yagdil Torah: 17100 W. Ten Mile Road, Southfield, 8:30-11:30 a.m. and 7:-9:45 p.m.

Dorfman Funeral Home: 30440 W. Twelve Mile Road, Farmington Hills, 2-5:30 p.m.

Yeshiva Beth Yahuda: 15751 Lincoln Dr, Southfield, 8:15 a.m. – 1:15 p.m. and 8:45 p.m. – 12:45 a.m.

Ohr HaTorah Synagogue: 15150 W. 10 Mile Rd, Oak Park, 8:00 – 11:30 a.m. and 2:45 – 5:30 p.m.

Kollel Institute of Greater Detroit: 15230 Lincoln St., Oak Park 8:00 – 11:00 p.m.

Bais Chabad Synagogue 15401 W 10 Mile Rd, Oak Park, MI 9:30 – 11:30 a.m.

March 20

Brede, Inc.: 19000 Glendale Ave., Detroit, 12-7:30 p.m.

Rite Aid: 24850 Greenfield Road, Oak Park, After 3:30 p.m.

Beaumont Medical Building, first floor, 3535 W. Thirteen Mile Road, Royal Oak, after 3 p.m.

Providence Park Novi Medical Building: 26850 Providence Parkway, Novi, after 1 p.m.

7-Eleven, Lincoln St., 15350 Lincoln, Oak Park, 9:20-11:30 p.m.

Ahavas Yisroel, 25952 Greenfield, Oak Park, 10 a.m.-12:30 p.m.

Kollel Institute of Greater Detroit: 15230 Lincoln St., Oak Park, 8-11:30 p.m.

Dovid ben Nuchim, 14800 Lincoln St., Oak Park, all day

Yagdil Torah: 17100 W 10 Mile Road, Southfield, 8-11 p.m.

PointView Products: 46986 Liberty Drive, Wixom, 8 a.m.-3:30 p.m.

Ohr HaTorah Synogogue: 15150 W. Ten Mile, Oak Park, 7:00 – 11:00 p.m.

Meijer: 5150 Coolidge Highway, Royal Oak, 10:30 a.m.-1:30 p.m.

One Stop Kosher: 25155 Greenfield Road, Southfield, 12-3:30 p.m.

Aldi: 26300 Greenfield Road, Oak Park, all day

Yeshiva Beth Yahuda: 15751 Lincoln Drive, Southfield, 10 a.m.-5 p.m.

The Natural Food Patch: 221 W. Nine Mile Road, Ferndale, 3-5:20 p.m.

Yeshiva Gedolah of Greater Detroit: 24600 Greenfield Roiad, Oak Park, 7:30-11 a.m.; 8-11 p.m.

18977 W. Ten Mile, Southfield: first floor, 9-6 p.m.

Target: 30333 Southfield Road, Southfield, 2-5 p.m.

March 19

Bank of America, 45194 Romeo Plank Road, Macomb Township, noon-2 p.m.

Building at 211 W. Fort St., Detroit, 10 a.m.-2 p.m. This building includes Detroit Economic Club, U.S. Department of Labor, U.S. Passport Office and more.

Beaumont Hospital, Royal Oak – 6th Floor, North Tower: 3601 W. Thirteen Mile Road, Royal Oak, 1-11 p.m.

Berkley Urgent Care, 3270 Greenfield Road, Berkley, 10 a.m.-1 p.m.

Congregation B'Nai Israel: 15400 W. Ten Mile Road, Oak Park, all day

Ahavas Olam: 15620 W. Ten Mile Road, Southfield, all day

Yeshiva Gedolah of Greater Detroit: 24600 Greenfield Road, Oak Park, all day

Kollel Institute of Greater Detroit: 15230 Lincoln St., Oak Park, all day

Dovid ben Nuchim, 14800 Lincoln St, Oak Park, all day

March 18

Kroger: 19853 W. Twelve Mile Road, Southfield, 8-11 p.m.

Berkley Medical Center: 1695 W. Twelve Mile Road, Berkley, 11:15 a.m.-3 p.m.

Meijer: 28800 Telegraph Road, Southfield, 1-4:30 p.m.

Yeshivas Darchei Torah School: 21550 W. Twelve Mile Road, Southfield, 9 a.m.-3:30 p.m.

Oakland County Circuit Court Building: 1200 N. Telegraph Road, Building 12E, Pontiac, 1:30-5 p.m.

ABC Warehouse: 24725 Southfield Road, Southfield, 3:30-7 p.m.

Universal Plumbing Supply: 14511 W. Eleven Mile Road, Southfield, 4:40-7:30 p.m.

Berkley Medical Center, 1695 W. Twelve Mile Road, Berkley, 1:30-4:30 p.m.

Walgreens, 7380 Orchard Lake Road, West Bloomfield, 9:30 p.m.-midnight

Kravings, 25270 Greenfield Road, Southfield, 9 p.m.-midnight

Beaumont Hospital, Royal Oak – Emergency Department and sixth floor North Tower: 3601 W. Thirteen Mile Road, Royal Oak, 2:30-11 p.m.

Beaumont Hospital, Royal Oak – Medical Office Building: 3535 W. Thirteen Mile Road, Royal Oak, 3-5 p.m.

Crowne Point Office Building, 25900 Greenfield, Oak Park, After 9 a.m.

Berkley Urgent Care, 3270 Greenfield Road, Berkley, 4-7 p.m.

Congregation B'Nai Israel: 15400 W. Ten Mile Road, Oak Park, all day

Ahavas Olam: 15620 W. Ten Mile Road, Southfield, all day

Yeshiva Gedolah of Greater Detroit: 24600 Greenfield Road, Oak Park, all day

Kollel Institute of Greater Detroit: 15230 Lincoln St., Oak Park, all day

One Stop Kosher Food Market: 25155 Greenfield Road, Southfield, all day

Dovid ben Nuchim: 14800 Lincoln St., Oak Park, all day

Zeeman's Bakery: 25258 Greenfield Road, Oak Park, 10 a.m.-1 p.m.

March 17

Yeshivas Darchei Torah School: 21550 W. Twelve Mile Road, Southfield, 9:00 a.m. – 3:00 p.m.

Beth Tefilo: 24225 Greenfield Road., Southfield, 8-11 a.m.

Lowe's Home Improvement: 28650 Telegraph Road, Southfield, 12:20-3:30 p.m.

Lowe's Home Improvement: 434 W. E. Twelve Mile Road., Madison Heights, 3-7 p.m.

Home Depot: 660 W. Twelve Mile Road, Madison Heights, 4:30-7 p.m.

Congregation B'Nai Israel: 15400 W. Ten Mile Road, Oak Park, all day

Ahavas Olam: 15620 W. Ten Mile Road, Southfield, all day

Yeshiva Gedolah of Greater Detroit: 24600 Greenfield Road, Oak Park, all day

Kollel Institute of Greater Detroit: 15230 Lincoln St., Oak Park, all day

One Stop Kosher Food Market: 25155 Greenfield Road, Southfield, all day

Delta Airlines flight #2234 from Baltimore to Detroit, landing at 11:40 a.m.

Ohel Moed Shamrei Emunah: 6191 Farmington Road, West Bloomfield, 6-8 p.m.

Beaumont Hospital, Royal Oak - Medical Office Building: 3535 W. Thirteen Mile Road, Royal Oak, 3-5 p.m.

March 16

Beth Tefilo: 24225 Greenfield Road, Southfield, 8 p.m.-11 p.m.

Congregation B'Nai Israel: 15400 W. Ten Mile Road, Oak Park, all day

Ahavas Olam: 15620 W. Ten Mile Road, Southfield, all day

Yeshiva Gedolah of Greater Detroit: 24600 Greenfield Road, Oak Park, all day

Kollel Institute of Greater Detroit: 15230 Lincoln St., Oak Park, all day

One Stop Kosher Food Market: 25155 Greenfield Road, Southfield

March 15

Young Israel of Oak Park: 15140 W. Ten Mile Road, Oak Park, after 1-6 p.m.

Kroger, 23675 Greenfield Road, Southfield, 12-3 p.m.

Beaumont Medical Building, first floor: 3535 W. Thirteen Mile Road, Royal Oak, 10 a.m.-2 p.m.

SKLD Bloomfield Hills: 2975 N. Adams Road, Bloomfield Hills, 12-3 p.m.

Westborn Market: 27659 Woodward Ave., Berkley, 12:30 – 3:30 p.m.

Jax Kar Wash: 27054 Woodward Ave., Royal Oak, 1-4 p.m.

Congregation B'Nai Israel: 15400 W. Ten Mile Road, Oak Park, all day

Ahavas Olam: 15620 W. Ten Mile Road, Southfield, all day

Yeshiva Gedolah of Greater Detroit: 24600 Greenfield Road, Oak Park, all day

Kollel Institute of Greater Detroit: 15230 Lincoln St., Oak Park, all day

One Stop Kosher Food Market: 25155 Greenfield Road, Southfield, all day

Crowne Point Office Building, 25900 Greenfield, Oak Park, 9-11 a.m.

Congregation B'Nai Israel: 15400 W. Ten Mile Road, Oak Park, all day

March 14

Congregation B'Nai Israel: 15400 W. Ten Mile Road, Oak Park, all day

Ahavas Olam: 15620 W. Ten Mile Road, Southfield, all day

Yeshiva Gedolah of Greater Detroit: 24600 Greenfield Road, Oak Park, all day

Kollel Institute of Greater Detroit: 15230 Lincoln St., Oak Park, all day

Measles symptoms

Symptoms of measles usually begin seven to 14 days after exposure, but can appear up to 21 days after exposure and may include:

High fever (may spike to over 104°F)

Cough

Runny nose

Red, watery eyes (conjunctivitis)

Tiny white spots on the inner cheeks, gums and roof of the mouth (Koplik Spots) that appear two to three days after symptoms begin

A rash that is red, raised, blotchy; usually starts on the face, spreads to the trunk, arms and legs three to five days after symptoms begin

Complications can include pneumonia, swelling of the brain, ear infections that result in permanent hearing loss, preterm births and low birth weight babies.

Anyone who was potentially exposed should watch for symptoms for 21 days after exposure.

More on freep.com:

There are nearly 400 reported cases of measles in the US. What are states doing about it?

Measles outbreak sparks debate over vaccine laws

If symptoms develop, health officials say you should not visit your doctor or hospital emergency room unless you call ahead so heath care providers can take precautions to prevent the exposure of other people.

People who don't have documentation of two measles (MMR) vaccines from a doctor or Michigan Care Improvement Registry (MCIR), or those who don't know whether they've been vaccinated, should contact their health care providers or visit a vaccine clinic.

Where to get the measles vaccine

The Oakland County Health Division is offering vaccinations 8:30 a.m.-6 p.m. Mondays and 8:30 a.m.-5 p.m. Tuesdays through Fridays at the following sites:

North Oakland Health Center, 1200 North Telegraph Road, Building 34 East, Pontiac

South Oakland Health Center, 27725 Greenfield Road, Southfield

Details: 800-848-5533.

The Wayne County Health Department offers walk-in vaccinations 8-11 a.m. and 12:30-4 p.m. Mondays, Tuesdays, Thursdays and Fridays as well as 11 a.m.-2 p.m. and 3:30-7 p.m. Wednesdays at 33030 Van Born Road, Wayne.

Details: 734-727-7101.

If you or someone you know has the measles in Michigan, contact Kristen Jordan Shamus: 313-222-5997 or kshamus@freepress.com. Follow her on Twitter @kristenshamus.