Until now, monkeypox was a somewhat rare disease of the Central and West African regions. Monkeypox and smallpox are related, but monkeypox disease is milder and rarely fatal. Both viruses are part of the Orthopoxvirus family (genus), which also includes cowpox and vaccinia.

Monkeypox was identified in 1958, and the first recorded human case was in 1970. Before this 2022 global outbreak, the few cases in the U.S. occurred in people who caught the virus abroad or got it through contact with animals.

Key points:

• Monkeypox is contagious from the earliest symptom until all scabs fall off.

• Getting vaccinated and avoiding close contact with sick people are the prevention options.

• Mask-wearing, hand-washing, and social distancing, which we all learned for COVID-19, also help prevent monkeypox transmission.

• Seeing a doctor online via video, or in-person at an office, are ways to see if a concerned person needs to be vaccinated, evaluated, tested, diagnosed, or treated.

• Testing requires an in-person visit, as there is currently no at-home rapid test.

• Vaccination is typically done at public health clinics. Clinic websites display local eligibility guidelines.

The 2022 monkeypox outbreak is different from previous outbreaks. Person-to-person monkeypox transmission is now happening outside of Africa, is occurring almost entirely in men who have sex with men (MSM), and is expected to spread from MSM to the global population of all men, women, and children. The speed and manner in which monkeypox will spread among the general population is not yet known. As of August 1, there have been more than 23,000 cases worldwide, with five deaths in Africa and four deaths outside of Africa. In this outbreak, 98.5% of the cases are outside the Central and West African countries where monkeypox was previously seen. 

Major outbreak countries and approximate case numbers (as of August 1, 2022) are:

• United States — 5,800.

• Spain — 4,300 (3.2% hospitalization rate; 2 deaths).

• Germany — 2,600.

• United Kingdom — 2,500.

• France — 1,900.

• Brazil — 1,300 (1 death).

• Netherlands — 900.

• Canada — 800.

• Portugal — 600.

Smallpox, related to but more serious than monkeypox, recorded its last known case 44 years ago in 1978. Before that, smallpox vaccine was a routine shot for the general population, but routine vaccinations stopped in the U.S. in 1972. Doctors are unsure if a smallpox vaccine injection received over 50 years ago can protect a person from monkeypox today.

Chickenpox is not related to monkeypox. Chickenpox is caused by varicella-zoster virus, a herpesvirus that also causes shingles.

What does monkeypox illness look like?

• Incubation period after catching the virus: 1–2 weeks.

  • A person is not contagious during incubation and does not have symptoms yet.

• Prodromal period is when initial or early symptoms appear. A person with any symptoms may be contagious.

  • Symptoms include fever, malaise, headache, weakness, and lymphadenopathy (swollen lymph nodes).

  • Sore throat, cough, or nasal congestion occur less commonly.

• Lymphadenopathy  (swollen glands) is common in monkeypox, but not in smallpox. With monkeypox, swollen lymph node glands:

  • First appear with onset of fever, 1–2 days before onset of rash, or rarely at the time rash starts.

  • May be generalized involving many different body locations, or localized to a few areas such as the neck, armpit, or groin areas.

  • May be on both sides of the body or just one side.

• Rash appears after the prodrome (fever starts before the rash), but some people get the rash as the first symptom. First lesions appear on the tongue and in the mouth (an enanthem, or a rash inside the body). A person is definitely contagious once any rash begins. Lesions on the skin:

  • Develop at one time and evolve together in an affected area, and thus are about the same size and at the same stage on any one part of the body.

  • Start on the face, spread to the arms and legs, and then to the hands and feet, including the palms and soles.

  • Spread to all parts of the body within 24 hours and tend to have more lesions on the face, arms, and legs (a centrifugal pattern).

  • Are well circumscribed and deep seated, with pustules often having a dimple in the center (central umbilication).

  • Are often painful until the itchy, crusted healing phase.

  • Evolve through four stages: macular, papular, vesicular, pustular; and they then scab over and resolve. Duration of the illness (prodromal + rash periods) is 2–4 weeks; durations of the rash stages are:

    • Macules: 1–2 days.

    • Papules: 1–2 days.

    • Vesicles: 1–2 days.

    • Pustules: 5–7 days.

    • Scabs: 7–14 days.

• Photographs of examples of monkeypox lesions:

  • Pictures provided by the CDC. 

  • Pictures provided by Eurosurveillance. 

• Severity of illness depends on a person’s underlying health and existing medical conditions, the route of exposure, and the strain of monkeypox virus, such as:

  • West African monkeypox — has milder disease, fewer deaths, and limited human-to-human transmission.

  • Central African monkeypox — has more severe disease, higher mortality, and easier person-to-person spread.

  • 2022 Global Outbreak monkeypox — might be caused by a modified strain similar to the West African strain but with milder disease. More time is needed to gather data, so better definition of strains will come in the near future.

Do you have to quarantine or isolate if exposed to monkeypox?

Contagiousness begins in the prodromal period, is present the entire rash period, and ends when all scabs have healed and fallen off. Self-quarantine and home isolation skills learned during the COVID pandemic should work well for persons exposed to or suffering from monkeypox.

• Quarantine
  While the incubation period between exposure and first symptoms is usually 1–2 weeks, it can be as long as 3 weeks. Because an exposed person can become contagious at some time up to 21 days after exposure, that person should consider self-quarantining for 3 weeks to avoid unintentionally spreading the virus to close contacts or others in their household or workplace. Quarantine is for people who were exposed but have no symptoms; isolation should begin if any symptoms appear.

• Isolation
  Patients who develop symptoms, such as fever or rash, should isolate themselves for the entire 2–4 week duration of their illness, from first symptoms (prodromal period) until all scabs have fallen off and their skin has healed (rash period). After healing and completing isolation, the skin may still have some pitted scars, darker skin areas (hyperpigmentation), or lighter skin areas (hypopigmentation). 

• Follow-up care 
  Follow-up care can be done through a video visit with one’s primary care doctor because almost all monkeypox cases are mild and do not cause problems after recovery.

• Am I contagious after recovery? 
  No, but doctors are uncertain how long the virus is still in semen or other genital fluids after the rash has gone away. To be safest, patients can avoid intimate contact with other people for three months after recovery, until researchers learn more about this issue.

• Am I immune after recovery? 
  Yes, doctors expect a person who recovers from monkeypox to have lifelong immunity, because people who recovered from smallpox had lifelong smallpox immunity. Researchers will gather more definitive data on this and publish their findings in the coming years.

Can you avoid catching monkeypox?

Yes, a person can avoid catching monkeypox by avoiding close contact with infected people or items contaminated with virus from infected people. Monkeypox can transmit via air droplets, but not as easily as COVID does. Methods for avoiding COVID, such as wearing masks, washing hands, and using gloves, should greatly help with avoiding monkeypox. People at high risk of catching monkeypox or who cannot avoid contact with infected people should contact their primary care doctors for advice, either online or in-person. The doctor may recommend a monkeypox vaccine if needed.

People who should be vaccinated include:

• Healthcare workers who will be caring for monkeypox patients, handling monkeypox lab specimens, or giving the attenuated virus (ACAM2000) monkeypox vaccine injections.

• Persons with confirmed recent exposure to monkeypox virus. The sooner an exposed person gets vaccinated, the better the outcome.

  • If vaccinated within four days of exposure, the person might not develop the disease at all.

  • If vaccinated between 4–14 days after exposure, the person’s disease severity may be milder than if not vaccinated.

Vaccine access is likely guided by each county’s public health department, due to the limited supply of vaccines and unique features of local outbreaks. Persons looking for a vaccine should get information from their local public health websites.

A concerned person can check their public health website to see what the eligibility requirements are to get a monkeypox vaccine in their city or county.

• Sometimes, no doctor visit is required for eligibility.

• If a video visit with one’s own doctor is needed for an evaluation or completion of a medical status form, download the form from the public health website and upload it to the doctor’s site.

  • During the video visit, one’s doctor can review the level of exposure risk and assess the situation. Lab tests may or may not be needed.

  • If one’s online doctor can complete any needed form, a patient can give the form to local public health to help get access to a monkeypox vaccine.

• Lab tests to confirm an infection require an in-person visit to a primary care doctor.

Which vaccines are available in the U.S.?

There are two vaccines currently available in the U.S.:

JYNNEOS (also called Imvamune or Imvanex) is approved for prevention of monkeypox and smallpox.

• JYNNEOS is a live but non-replicating vaccine. It is presumed safe to use in immunocompromised patients or during pregnancy and breastfeeding, but such patients should first discuss the benefits and risks with their primary care doctor.

• Eligible group — adults at high risk for catching monkeypox, who have not gotten a smallpox vaccine in the past three years.

  • Children under 18 are not eligible, but the CDC or FDA may create a program for vaccinating children if this outbreak continues to spread.

• Dose — 2 injections, given 4 weeks apart.

• Protection — is considered good by two weeks after the second dose.

• Availability — not enough. About one million doses will be available in the U.S. by August 2022, increasing to about seven million by mid-2023.

• Possible side effects reported after getting the JYNNEOS vaccine:

  • Injection site reactions include pain, redness, swelling, induration (skin firmness), or itching.

  • General reactions include muscle pain, headache, fatigue, nausea, or chills.

ACAM2000 is approved for prevention of smallpox but may also be used for prevention of monkeypox.

• ACAM2000 is a live virus vaccine that replicates and can transmit to close contacts of the vaccinated person. It is not recommended for people or households with certain health conditions, such as a weakened immune system, skin conditions like eczema, or pregnancy.

• Eligible group — persons age one year or older who are at high risk for catching monkeypox.

• Dose — one injection, with boosters every three years if needed.

• Protection — is considered good by four weeks after the first dose.

• Availability — is adequate. ACAM2000 is the less-preferred monkeypox vaccine for the general population, due to its higher risk of side effects, so the use of ACAM2000 is less.

• Possible side effects reported after getting the ACAM2000 vaccine:

  • Injection site reactions, lymphadenitis (swollen, inflamed lymph nodes).

  • General reactions such as malaise, fatigue, fever, myalgia, or headache.

  • Urticaria, folliculitis; skin reactions on the face, nose, mouth, lips, genitalia, or anus.

  • Myocarditis, pericarditis, encephalitis, encephalomyelitis, encephalopathy, progressive vaccinia, generalized vaccinia, severe vaccinial skin infections, erythema multiforme major (Stevens-Johnson syndrome), eczema vaccinatum resulting in death, eye complications, blindness, fetal death.

  • ACAM2000 contains live virus that can be transmitted to persons who have close contact with the newly vaccinated person. Vaccine side effects can occur in the person to whom the vaccine virus unintentionally got transmitted to.

The level of protection by either vaccine in the current monkeypox outbreak will not be known until time allows more data to be collected.

• Past data from Africa suggests 85% effectiveness.

• Vaccinated people should continue to protect themselves by avoiding close contact with monkeypox-infected persons.

What if you might have monkeypox now?

A concerned person should do a video visit or an in-person visit with their primary care doctor. Because monkeypox is contagious to others, it is wise to contact a doctor first by video, text-messaging, or phone, instead of dropping in at their office unexpectedly. However, people who are possibly infected but have no access to online doctors or in-person appointments can contact their local public health department for help, or go to an urgent care clinic or emergency room.

During a video visit or in-person appointment, the doctor may ask about what types of close contact the patient has had with any suspected or known monkeypox case in the past 21 days.

Types of close contact with an infected person can include:

• Providing home care to an infected person.

• Indirect contact, such as sharing sexual partners with an infected person.

• Sex with an infected person, such as vaginal, oral, or anal sex.

• Intimate contact aside from sex, such as cuddling, kissing, touching the person’s genitals or anus, or sharing sex toys.

• Sharing with an infected person:

  • Food, utensils, or dishes.

  • Towels, bedding, or clothing.

  • Bathrooms, toilets, sinks, or showers.

  • Transportation such as carpooling, riding a bus, or using a taxi or ridesharing service such as Uber.

• Casual face-to-face contact, such as being unmasked and within six feet of an unmasked infected person, for more than three hours.

Other risk factors may exist. A doctor also wants to learn whether or not their patient:

• Had close contact with MSM (men who have sex with men) at a bar, party, or other social event.

• Traveled recently to places where monkeypox is endemic or breaking out.

• Is a healthcare worker who might have interacted with an infected person at work.

• Is immunocompromised, such as due to HIV, AIDS, cancer chemotherapy, biologic medications, or use of prednisone or other steroids.

• Had contact with an animal or animal products from places where such animals have been found to have monkeypox. Monkeypox can infect a wide range of mammals such as monkeys, apes, anteaters, hedgehogs, prairie dogs, squirrels, and shrews.

From a video visit or in-person evaluation, the doctor can decide whether a patient is a:

• Suspect case 
  The patient has a new rash that looks like monkeypox, and/or

  • meets one of the “close contact or risk factor” criteria described above and seems suspicious for monkeypox.

• Probable case 
  The patient has a positive orthopoxvirus DNA PCR test, and did not recently get an orthopoxvirus vaccine before testing.

  • Less common Orthopoxvirus tests used to show a probable case include:

    • Immunohistochemical or EM test, if positive.

    • Serum IgM antibody, if positive at 4–56 days after rash onset.

• Confirmed case 
  The patient has a positive monkeypox virus DNA PCR test.

  • Less common monkeypox virus tests used to show a confirmed case include:

    • Next-Generation Sequencing (NGS) test, if positive.

    • Viral culture, if positive.

• Case of something else other than monkeypox 
  If the patient:

  • Has no rash even after five days of prodromal symptoms described above, OR

  • Has negative orthopoxvirus or monkeypox virus lab tests, OR

  • Gets diagnosed with a different illness that is responsible for their symptoms.

    • Note — because it is possible to have both monkeypox at the same time as another rash disease such as syphilis, herpes, chickenpox, or shingles, the doctor can monitor or do additional tests if needed.

How do you get a lab test for monkeypox?

There is no rapid monkeypox test for home use. An in-person visit to a primary care doctor, urgent care clinic, emergency room, or public health testing site is needed in order to swab the lesions of a suspected monkeypox rash in order to test for the virus.

Labs such as LabCorp or Quest Diagnostics can run monkeypox tests on swabs received from doctors’ clinics, but labs themselves do not swab patients for samples. Thus, a patient cannot go directly to a lab to ask for a test.

Is there medication that treats monkeypox?

There is no monkeypox medication for normal people who happen to catch the virus and who are not at high risk for severe disease.

Tecovirimat (also called TPOXX) is an antiviral drug approved for treating smallpox. TPOXX may be used to treat monkeypox in patients with a high risk of severe monkeypox disease. Such patients should see their in-person primary care doctor because additional forms are needed to request authorization to use TPOXX. In some cases, Infectious Disease specialists may be consulted to help care for these sick patients.