If you were exposed to measles, call your healthcare provider or local health department right away, before you walk into a clinic or emergency room. If you are not immune, New Jersey's October 2024 exposure guidance says the MMR vaccine may help when it is given within 72 hours of first exposure, and immune globulin may help within 6 days. The CDC's August 2026 measles page says “within the last few days” instead, so ask your provider for your exact deadline.
What do I do first after a measles exposure?
As of November 2026, the CDC measles exposure guidance says to call your healthcare provider immediately. Tell them you were in the same place as someone with measles, or with signs of measles who has not been diagnosed. They can check whether you are immune, arrange an evaluation that will not put other patients and staff at risk, and advise you on ways to lower your risk.
You count as exposed if you shared indoor space with someone who has measles, such as a room, home, office or waiting room. You also count if you went into that space up to two hours after the person left. The New Jersey exposure guidance sets out that definition.
People can spread measles before they know they are sick. Colorado's Colorado measles guidance for schools and child care says the contagious period runs from four days before the rash appears until four days after it appears. That is why the call matters even if you feel fine.
If you do not have a primary care provider, UC Davis Health advises calling your county's UC Davis Health measles guidance is written for patients, and it recommends your county public health department as the next call. In New Jersey, the New Jersey local health department directory lists local offices. In Colorado, the state's public health line at 303-692-2700 (303-370-9395 after hours) is the reporting line for schools, child care and clinicians who report suspected or confirmed cases. If you were exposed, call your provider or local health department.
How do I know whether I am immune?
New Jersey's guidance says you are generally considered immune if one of these is true:
- You had measles before, and a lab confirmed it.
- A blood test shows antibodies that protect against the virus.
- You have written records of adequate MMR vaccination. For preschool-age children and adults not at high risk, that means one or more doses given on or after the first birthday. For school-age children and adults at high risk, including college students, health care workers and international travelers, it means two doses.
- You were born before 1957. New Jersey notes this is generally, but not always, enough. Colorado's guidance says a laboratory test can confirm immunity.
Start with your records. Your provider, your child's school, a college, a past employer, the military or your state immunization registry may have them. If you cannot find them, a blood test can show immunity. New Jersey's guidance says that test is likely to cost more and may take two doctor's visits.
How long do I have for the MMR vaccine and immune globulin?
Plan around the earliest timing below, and confirm your own deadline the day you call.
| Step | Timing |
|---|---|
| Call your provider or health department | As soon as possible; the CDC says immediately |
| MMR vaccine | May help if given within 72 hours of first exposure (New Jersey, October 2024) |
| Immune globulin | May help if given within 6 days of first exposure (New Jersey, October 2024); the CDC page says “within the last few days” |
| Quarantine if you are not immune and got neither | Up to 21 days; New Jersey starts it on day 5 after first exposure and runs it through 21 days after your last exposure |
| Symptoms may appear | 7 to 15 days after contact (CDC); usually 8 to 14 days, range 7 to 21 (Colorado) |
| Contagious period | From 4 days before the rash to 4 days after (Colorado, New Jersey) |
Immune globulin is a blood product that contains antibodies to the measles virus. New Jersey's guidance says it may be given to some infants under 12 months, pregnant women, people with weakened immune systems, and others who cannot get the vaccine for medical reasons. Your clinician weighs the risks and benefits with you.
Costs and coverage differ by plan and location. Before you go in, ask the office what the MMR vaccine, immune globulin and any blood test will cost you.
How long should I quarantine after measles exposure?
If you are not immune and do not get the vaccine or immune globulin in time, you may be advised to stay home for up to 21 days. New Jersey's guidance says you may be asked to stay home and away from work, school and public places for 21 days. Public health officials set your exact dates.
New Jersey's guidance says that if you get the vaccine within 72 hours, you might not need quarantine. If you get it after 72 hours, you will need to quarantine for 21 days. Colorado's school and child care guidance says unvaccinated students and staff who cannot receive post-exposure treatment should be kept out of school for at least 21 days after exposure.
While you are in quarantine, New Jersey's guidance lists these steps:
- Stay in your room or a designated area, and avoid contact with others in the home.
- Wear a mask in shared rooms.
- Leave home only for emergency medical care, and wear a mask if you do.
- Wash your hands often with soap and water. Alcohol-based hand sanitizer with at least 60% alcohol can be used when hands are not visibly dirty.
- Household members who are not immune, or are not sure, should consider getting the vaccine.
What if I was exposed to measles but I am vaccinated?
New Jersey's guidance says that if you are immunized or have other proof of immunity, you do not need to be quarantined and may continue your normal activities. Vaccination protects most people. The same guidance says that if 1,000 people each get two doses, about 997 of them will be protected. UC Davis Health notes that about 3 in 100 people who get both doses remain susceptible to infection.
Ask whether your records count as proof of immunity for this exposure. If symptoms appear, call ahead, wear a mask, and stay home until the fifth day after the rash appears, as the CDC advises.
How long after exposure do symptoms show up?
The CDC says measles symptoms appear 7 to 15 days after contact with the virus. Colorado's guidance says the usual range is 8 to 14 days, with 7 to 21 days as the full range. Measles usually starts with fever, cough, runny nose and red eyes, followed by a rash.
When do I go straight to the emergency room?
If you are sick with measles and your symptoms get rapidly worse, or you have any of these signs, the CDC says to go to the emergency department right away and not wait:
- Trouble breathing, or breathing faster than normal
- Pain when breathing or coughing
- Dehydration, such as a dry nose and mouth, urinating less, or crying without making tears
- A fever or headache that will not stop
- Confusion, decreased alertness or severe weakness
- A blue color around the mouth, low energy, or difficulty feeding in young children
Have someone call ahead so the hospital knows a person with measles is coming. UC Davis Health advises anyone ages 2 and older to wear a mask, with N95 or KN95 masks best.
What do I still need to find out?
Your exact dates depend on when you were exposed and what your records show. Ask your provider or local health department to set them for you, and write them down.
Before you act: a short checklist
- Call your provider or local health department today, before you visit.
- Find your MMR record or other proof of immunity.
- Write down when and where you were exposed.
- Ask whether the MMR vaccine or immune globulin is right for you, and by what date.
- Ask when you can no longer make other people sick, and how long you need to stay away from schools, hospitals and childcare centers.
By SterlingMedicalCenter.org Editorial Team
This article is for general information purposes only and does not constitute medical advice. Consult your doctor or qualified healthcare provider before making changes to your health routine.