Tag: measles exposure

What Are the Signs and Symptoms of Measles?

The first measles vaccine was developed in 1963 and its use led to a quick drop in measles cases in the United States.

In fact, as most people know, the endemic spread of measles was declared eliminated in the United States in 2000.

What does that mean?

A typical case of measles, as described in 1920, doesn't sound very mild or marvelous as some folks claim it to be.
A typical case of measles, as described in 1920, doesn’t sound very mild or marvelous as some folks claim it to be.

For one thing, it means that many people in the United States have never actually seen anyone with measles.

What Are the Signs and Symptoms of Measles?

As we are seeing more and more measles cases each year, it makes it important for everyone to learn how to recognize what measles looks like. Measles is so contagious, that missing just one case can lead to a lot of other people getting exposed unnecessarily and can keep an outbreak going.

So what does measles look like?

Call before you go to the ER or to see your doctor if you think your child has measles so that you don't put others at risk.
Call before you go to the ER or to see your doctor if you think your child has measles so that you don’t put others at risk.

After being exposed, kids with measles will develop:

  • a high fever
  • cough and/or runny nose
  • red, watery eyes with photophobia (dislike of bright light)
  • sore throat
  • irritability
  • decreased appetite

That sounds like many other viral infections that kids get though, which is why measles is so hard to diagnose, at least at the beginning stages of the illness, when kids only have the first signs of measles – the fever, cough, runny nose, and conjunctivitis.

Koplik spots, small gray-white spots in your mouth, are another clue that a child might have measles. They can develop on the second or third day of fever.

Next, after having the high fever for 3 to 5 days, kids develop a worsening fever and the classic measles rash. It is important to note that you are contagious well before you get the rash though, up to about four days before the rash develops, providing plenty of chances to expose others before you ever know you have measles.

“It usually begins as flat red spots that appear on the face at the hairline and spread downward to the neck, trunk, arms, legs, and feet. Small raised bumps may also appear on top of the flat red spots. The spots may become joined together as they spread from the head to the rest of the body.”

Measles Signs and Symptoms

While many diseases have a fever with or followed by a rash, it is very characteristic of measles that the fever continues for a few more days as the child develops the rash.

“You’ll usually feel most ill on the first or second day after the rash develops.”

Measles Symptoms

This is when most kids get diagnosed, typically with laboratory confirmation.

Unfortunately, because of the high fever and irritability, they may have sought medical attention a few times and could have exposed a lot of people already, especially as you continue to be contagious until you have had the rash for at least four days.

“After a few days, the fever subsides and the rash fades.”

Measles Signs and Symptoms

All together, these classic measles symptoms typically last about a week. As the rash fades, parents might notice staining and then a fine desquamation (skin peeling).

Of course, if any complications develop, the symptoms can last much longer.

What complications? Remember, measles was once called a harmless killer

Complications of measles can include:

  • ear infections
  • diarrhea
  • croup
  • pneumonia
  • seizures
  • encephalitis
  • myocarditis

And tragically, some kids don’t survive having measles.

“Furthermore, the risk of contracting other infections or dying remains high for several months after recovery from acute measles infection.”

Treating Measles in Children

And although most do survive the acute infection, we know that these kids are still at risk for getting other infections in the next few months and are at a later risk for SSPE.

Get vaccinated. Stop the outbreaks. There is no good reason that our kids should have to get measles today.

More on the Signs and Symptoms of Measles

About Those Vaccine Strains in Measles Outbreaks…

A lot happens to control and contain a measles outbreak these days.

For one thing, you have to confirm that everyone with measles symptoms actually has measles. If you miss anyone, because measles is so contagious, then they could expose other people and the outbreak will keep getting bigger.

How do they confirm who has measles and who doesn’t?

While you could just make a clinical diagnosis, simply relying on the person’s history and pattern of symptoms, typically everyone just gets tested.

About Those Vaccine Strains in Measles Outbreaks…

What kind of testing?

“Laboratory confirmation is essential for all sporadic measles cases and all outbreaks. Detection of measles-specific IgM antibody and measles RNA by real-time polymerase chain reaction (RT-PCR) are the most common methods for confirming measles infection. Healthcare providers should obtain both a serum sample and a throat swab (or nasopharyngeal swab) from patients suspected to have measles at first contact with them. Urine samples may also contain virus, and when feasible to do so, collecting both respiratory and urine samples can increase the likelihood of detecting measles virus.”

Measles For Healthcare Professionals

It depends, but often a throat swab or a throat swab and urine are collected for PCR testing, especially if it has been 7 or fewer days since the patient came down with their rash.

If it has been longer than 7 days, then testing using urine and blood specimens can be performed.

“Molecular analysis can also be conducted to determine the genotype of the measles virus. Genotyping is used to map the transmission pathways of measles viruses. The genetic data can help to link or unlink cases and can suggest a source for imported cases. Genotyping is the only way to distinguish between wild-type measles virus infection and a rash caused by a recent measles vaccination.”

Measles For Healthcare Professionals

Because many people get vaccinated during an outbreak and a rash and fever is a side effect of the MMR vaccine, testing becomes very important in those who were recently vaccinated.

Statistics from the 2015 Disneyland measles outbreak...
Statistics from the 2015 Disneyland measles outbreak. Anti-vaccine folks, this slide doesn’t mean what you think it means.

After getting vaccinated, testing helps confirm that someone has vaccine strain measles and not wild type, a vaccine reaction, and don’t actually have measles.

“Here, we describe a real-time reverse transcription-PCR (RT-PCR) method that detects the vaccine genotype (MeVA RT-quantitative PCR [RT-qPCR]) and that can provide rapid discrimination between wild-type-virus infections and vaccine reactions.”

Roy et al on Rapid Identification of Measles Virus Vaccine Genotype by Real-Time PCR

An no, the vaccine reaction is not that they developed measles! They developed a rash and/or fever, a common side effect of the MMR vaccine.

“During outbreaks, measles vaccine is administered to help control the outbreak, and in these situations, vaccine reactions may be mistakenly classified as measles cases.”

CDC on Genetic Analysis of Measles Viruses

So the reports that you might have seen that 31 people in the California measles outbreak had a vaccine strain of measles aren’t true. There were at least 31 people who were recently vaccinated during the outbreak and had a rash and/or fever, and they tested positive for the vaccine strain, proving that they weren’t actually part of the outbreak. None of them actually had measles though.

Has anyone ever gotten the measles after being vaccinated?

“Vaccine‐associated measles is a possible, but extremely rare event.”

Sood et al on Vaccine‐associated measles in an immunocompetent child

Yes, there are a few case reports.

Very rare case reports.

Who's to blame for low immunization rates and continuing outbreaks?
Who’s to blame for low immunization rates and continuing outbreaks?

We know who’s responsible for the rise in measles outbreaks and no, it ain’t folks who have recently been vaccinated. Vaccines are safe and necessary.

Get vaccinated. Stop the outbreaks.

More on Vaccine Strains in Measles Outbreaks

What Are Anti-Vaccine Folks Saying About the Measles Outbreaks?

If your kids are intentionally not vaccinated and you live in an area where there is a big measles outbreak, then you are hopefully saying, “where can I get an MMR for my child.”

There were 23 measles cases in Orange County in 2014 and an additional 35 cases in 2015.

And you hope that your “vaccine friendly” pediatrician has vaccines and will actually vaccinate your kids…

What Are Anti-Vaccine Folks Saying About the Measles Outbreaks?

And while many parents change their minds and ending up vaccinating their kids when faced with an outbreak, you likely won’t be surprised about what some folks think or say during an outbreak of measles.

Actually, the CDC said that there was no ongoing, single, multi-state outbreak of measles. Instead, there were lots and lots of little outbreaks.

Yes, these are the things anti-vaccine folks say to try and reassure themselves that they made a good decision to intentionally leave their kids unvaccinated and at risk for a life-threatening disease. One that their kids are even more at risk of getting, because there is an outbreak in their community.

Of course, most folks in measles outbreaks are unvaccinated. It isn’t spread by those who are vaccinated.
And these outbreaks are never caused by shedding or a vaccine strain of measles.
Reporting about outbreaks to help get them under control is not media hysteria. And yes, measles made the headlines in the pre-vaccine era.
That’s because measles didn’t kill everyone who got sick. But there were about 500 measles deaths each year in the United States in the pre-vaccine era. Those folks all had stories, whether or not you ever heard them.
Vitamin A as a treatment for measles is typically helpful if you have a vitamin deficiency. It is probably not going to be very helpful in a developed country.
And yet measles was referred to as a harmless killer, because while many kids didn’t recover, others died or had complications, like encephalitis.
Measles is not a deadly disease if you don’t ever get it. And are you really not going to vaccinate your kids because the Brady Bunch had an episode about the measles?
This copypasta links to a post that left out the part of the article that told folks to get vaccinated…
God I hope that measles parties aren’t going to become a thing.
What scares folks about measles? Anti-vaccine misinformation about vaccines.

While you’re researching measles, do a little research about vaccines too.

Yes, a woman who got caught up in the 2015 measles outbreaks in Washington died.
Yes, a woman who got caught up in the 2015 measles outbreaks in Washington died.

Your kids will feel better if they are vaccinated and protected and don’t have measles.

More on What Anti-Vaccine Folks Are Saying About the Measles Outbreaks

The Pacific Northwest Measles Outbreak of 2019

Breaking News – There is 1 new case in Clark County (62 cases), bringing the total case count to 67 cases.

It started with a confirmed case of measles in a child in late December.

The Pacific Northwest measles outbreak on 2019 started when a child exposed others in the area in late December.

There were soon reports of more cases.

The Clark County measles outbreak quickly grew.

And more cases.

The Pacific Northwest Measles Outbreak of 2019

But the measles cases didn’t stay in Clark County.

Two of the unvaccinated kids from Clark County traveled to Hawaii while they were contagious.
Two of the unvaccinated kids from Clark County traveled to Hawaii while they were contagious.

As with other recent large measles outbreaks, cases soon spread to neighboring counties.

As of late January, there are now measles cases linked to this ongoing outbreak in Clark County and King County (Washington) and Multnomah County (Oregon).

The rapid growth of the outbreak led Clark County to declare a local public health emergency and Washington’ governor to declare a State of Emergency in all counties in the state of Washington.

“The measles outbreak and its effects impact the life and health of our people, as well as the economy of Washington State, and is a public disaster that affects life, health, property or the public peace.”

Governor Jay Inslee on proclaiming a State of Emergency

Why so much concern?

Are you familiar with the immunization rates in this part of the country? About the only good thing you can say about Washington’s immunization rates are that they are better than Oregon‘s…

Washington has one of the highest rates of exemptions in the United States.

That’s right.

High non-medical vaccine exemption rates and low vaccination rates. A recipe for very large outbreaks of vaccine-preventable diseases, especially measles which is so highly contagious.

Immunization rates by county in Washington.

And a recipe for disaster. These outbreaks are getting harder to control, are lasting longer, and are getting bigger and bigger.

Also remember that the last measles death in the United States, in 2015, was a woman who got caught up in a measles outbreak in Clallam County. Why didn’t that trigger folks in the area to get Vaccinated?

Pacific Northwest Measles Outbreak of 2019
Clark County (WA)62 cases
King County (WA)1 case
Multonomah County (OR)4 case
 67 cases

How many of them are vaccinated? Anti-vaccine folks are pushing hard to convince folks that everyone in the outbreaks are vaccinated. Don’t believe them!

As in most outbreaks, almost all of the people in this outbreak are unvaccinated.

How many people will get sick in the Pacific Northwest Measles Outbreak of 2019 before it ends?

You will have to make an extra appointment if you followed his immunization plan and left your kids unvaccinated and at risk during this outbreak.
You will have to make an extra appointment if you followed his immunization plan and left your kids unvaccinated and at risk during this outbreak.

Are parents going to keep listening to anti-vaccine folks who push the idea that measles isn’t that bad and make you think that it is riskier to get vaccinated?

Are they going to realize that unless they are malnourished or have a vitamin deficiency, that taking extra vitamin A that you order from someone’s online store will not reduce their risk of severe complications if their unvaccinated child gets measles?

“Please contact your pediatrician or doctor if your child is scary sick, struggling to breathe or unable to eat or very lethargic or otherwise seriously ill. Let them know you are worried they may have measles so they can arrange not to contaminate the waiting room or the whole office.”

Paul Thomas, Integrative Pediatrician

Getting vaccinated can help keep your kids from getting “scary sick” from measles…

“The above recommendations are informational only. Please consult with your doctor before implementing anything you might learn here.”

Paul Thomas, Integrative Pediatrician

The only good advice he gives.

Anti-vaccine misinformation has gotten us to the place where these outbreaks are becoming more common. Vaccinate your kids so they don’t get measles and don’t expose anyone else.

And for the anti-vaccine folks who are asking:

  • it isn’t going to be shedding or a vaccine strain that caused the outbreak
  • everyone or almost everyone in the outbreak is going to be unvaccinated
  • the measles vaccine does work against all the different genotypes of measles
  • more people don’t die from getting the MMR or any other vaccine than from the diseases they protect us against
  • whether the death rate of measles is 1 in 1000 or 1 in 10,000 cases, remember that just before the measles vaccine came out, in the early 1960s, nearly 500 people would die of measles each year. And it isn’t that a person dies after 1,000 or 10,000 cases. With more cases, there is just a higher chance that someone will eventually die.

And you are still worried about the MMR vaccine because anti-folks are still scaring you away from vaccinating and protecting your kids.

Vaccines are safe and necessary with few risks. There is no good reason that we should still have outbreaks like this.

More on The Pacific Northwest Measles Outbreak of 2019

Updated February 18, 2019

How Often Should You Do Vaccine Titer Testing?

We sometimes hear about folks doing vaccine titer testing.

A vaccine titer is a blood test that can determine whether or not you are immune to a disease after you get a vaccine.

While that sounds good, after all, why not check and be sure, it has downsides. Chief among them is that the results aren’t always accurate.

That’s right. You can sometimes have a negative titer test, but still be immune because of memory B cells and the anamnestic response.

How Often Should You Do Vaccine Titer Testing?

So how often should you do vaccine titer testing?

It depends, but most folks might never have it done!

Why not?

Vaccines work very well, so you would typically not need to routinely check and confirm that you are immune after being vaccinated. And, this is also important, the vaccine titer tests don’t always work that well, titer testing isn’t available for all vaccines (you can’t do titer testing for Hib and pertussis), and the testing can be expensive.

So we usually just do the testing (a quantitative titer) for folks that are in high risk situations, including:

  • pregnancy – rubella titer only (HBsAg is also done, but that’s not a vaccine titer test, but rather to see if you are chronically infected with hepatitis B)
  • healthcare workers – anti-HBs (antibody to the hepatitis B surface antigen to confirm immunity after being vaccinated)
  • students in nursing school and medical school, etc. – anti-HBs
  • children and adults exposed in an outbreakmeasles, chicken pox, mumps, etc., but only if we are unsure if they were previously vaccinated and protected
  • after a needlestick injury, etc. – to confirm immunity to hepatitis B
  • babies born to a mother with hepatitis B – to confirm that their hepatitis B vaccine worked

Vaccine titer testing might also be done for:

  • internationally adopted children – to confirm that they are immune if we unsure about all of the vaccines the child got in other countries
  • children and adults with lost vaccine records – to confirm that they are immune, since we are unsure about all of the vaccines they got
  • evaluation of children and adults with immune system problems – to help identify what immune system problems they might have – typically involves checking pneumococcal titers, giving Prevnar, and then checking pneumococcal titers again
  • people at continuous or frequent risk for rabies – rabies titer testing every 6 months to 2 years
  • patients with inflammatory bowel disease, before starting immunosuppressive therapy – hepatitis A and hepatitis B titers, as they might be at increased risk for hepatitis

While checking titers is easy, it is sometimes harder to know what to do with the results you get.

Of all of these different titers, only one tells you that you are immune due to vaccination.
Of all of these different titers, only one tells you that you are immune due to vaccination.

It is especially important to know that:

  • most people don’t need to have their titers checked routinely if they are not in one of the high-risk groups noted above
  • it isn’t practical to get titers tested as a method of potentially skipping one or more doses of your child’s vaccines, after all, if the titer is negative, then you are still going to have to get vaccinated
  • a healthcare provider with a negative measles titer after two doses of the MMR vaccine does not need another dose of vaccine
  • a healthcare provider who has anti-HBs <10 mIU/mL (negative titer) after three doses of the hepatitis B vaccine should get another dose of vaccine and repeat testing in 1 to 2 months – if still <10 mIU/mL, they should then get two more doses of hepatitis B vaccine (for a total of 6 doses) and repeat testing. If still negative, these documented nonresponders will need HBIG as post-exposure prophylaxis for any future hepatitis B exposures, but no further doses of hepatitis B vaccine.
  • vaccinated women of childbearing age who have received one or two doses of rubella-containing vaccine and have rubella serum IgG levels that is not clearly positive should be administered one additional dose of MMR vaccine, with a maximum of three doses, and should not be tested again
  • postvaccination titer testing is not recommended after the chicken pox vaccine
  • in addition to not being able to test titers for pertussis and Hib immunity, it is becoming difficult to test poliovirus type 2 titers, as the test uses a live virus that isn’t routinely available anymore (type 2 polio has been eradicated)

Still think you need vaccine titer testing?

More on Vaccine Titer Testing

News on the Latest Measles Outbreaks of 2019

Breaking News – 1 new cases in Washington (see below).

2019 has just started, but we already have reports of measles cases and exposures in at least 152 people in 9 states, including Colorado (1), Connecticut (3), Georgia (3), Hawaii (2), Kentucky (1), Illinois (4), New York (65), Oregon (5), Texas (7), and Washington (63).

And large, ongoing outbreaks in New York (Brooklyn and Rockland County) and the Pacific Northwest.

Measles is still spreading in New York.

There are also many reports of measles outbreaks in Europe.

2019 Measles Outbreaks

Since there were so many ongoing measles outbreaks in 2018, it shouldn’t be surprising that we are getting off to a quick start in 2019.

Recent cases and exposures include:

  • someone in Oregon who exposed other people in Portland (Jan 2), The Dalles (Dec 29 and 31, 2018), and Hood River (Dec 30, 2018)
  • an unvaccinated toddler in Monroe County, New York who had recently traveled to Ukraine
  • 9 new cases in Rockland County, New York (105 total)
  • 3 new cases in the Borough Park and Williamsburg sections of Brooklyn (55 total)
  • 3 new cases in Rockland County, New York (108 total)
  • a new outbreak in Clark County, Washington involving two unvaccinated children who exposed others on Jan 6 and 7 and an additional 11 suspected cases
  • 6 new cases in Rockland County, New York (114 total)
  • as expected, 12 more cases in Clark County, Washington (14 total) – all children, all unvaccinated (one unverified), with multiple exposures in Vancouver, including 5 different schools, 2 churches, and 6 health care facilities
  • 3 new cases in the Borough Park section of Brooklyn (58 total)
  • an adult in Denver, Colorado who became sick while traveling internationally and exposed others in Denver from Jan 10-14
  • 2 more cases in Clark County, Washington (16 total), with 5 more suspected cases remaining and exposures in Battle Ground (Jan 8 and 14) and Vancouver (Jan 14 and 15)
  • 2 kids from the Washington outbreak had traveled to Hawaii while contagious (January 4 to 13)
  • 2 residents of the metro Atlanta area, with exposures between Jan 7 to 14, although there is some speculation that these cases were also travelers from the Washington outbreak
Are these cases part of the Washington outbreak?
After 19 cases and an exposure at the Portland Trail Blazers game, Clark County has declared the measles outbreak to be a public health emergency.
After 19 cases and an exposure at the Portland Trail Blazers game, Clark County has declared the measles outbreak to be a public health emergency.
  • 3 more cases in Clark County, Washington (19 total), with 7 more suspected cases remaining and exposures in Camas (Jan 10- 15), Portland (Jan 11 and 14), and Vancouver (Jan 11 to 16), leading the Clark County Council Chair Eileen Quiring to declare a public health emergency.
  • 2 new cases in Clark County, Washington (21 total), with 4 more suspected cases remaining and exposures in Vancouver (Jan 7 to 11)
  • 4 new cases in the Borough Park and Williamsburg sections of Brooklyn (62 total)
  • 2 new cases in Rockland County, New York (118 total)
  • 2 new cases in Clark County, Washington (23 total), with 2 more suspected cases remaining and exposures in Vancouver (Jan 15 and 19) and Portland (Jan 15-16), including at the Portland International Airport (where did they go?)
  • 4 new cases in Rockland County, New York (122 total)
  • a case in the Champaign-Urbana Public Health District in Illinois with multiple exposures (Jan 12 to 19) including the University of Illinois in Urbana and Champaign
  • 2 new cases in Clark County, Washington (25 total), with 12 more suspected cases!
  • a case in King County, Washington that is linked to the outbreak in Clark County
  • 5 new cases in Clark County, Washington (30 total), with 9 more suspected cases!
  • a case in Multnomah County, Oregon that is linked to the outbreak in Clark County and with exposures (Jan 20 to 23) in Gresham, Wood Village, and Troutdale
Hopefully, no kids with immune system problems were exposed to these kids with measles.
Hopefully, no kids with immune system problems were exposed to these kids with measles.
Almost all of the measles cases in Rockland County are unvaccinated.

What kind of measles year will 2019 turn out to be? Unfortunately, we already have the potential for another record year…

These outbreaks are a great reminder to review the special vaccine travel requirements, including that adults who “plan to travel internationally should receive 2 doses of MMR at least 28 days apart,” that infants traveling abroad can get their first dose of MMR as early as age 6 to 11 months, with a repeat dose at age 12 months, and that “children aged who are greater than or equal to 12 months need 2 doses of MMR vaccine before traveling overseas,” even if they aren’t four to six years old yet.

For More Information On Measles Outbreaks:

Updated on February 18, 2019

How Contagious Is Measles?

Did you hear about the folks in New York who got quarantined isolated on the Emirates plane from Dubai?

Turns out that about 10 passengers had the flu or other cold viruses.
Although the worry was likely about MERS, it turns out that about 19 passengers had the flu or other cold viruses.

News like that and folks getting exposed to other infectious diseases, probably has them wondering just how contagious these diseases are. Do you have to be sitting next to someone to get them? In the same row? On the same floor?

Understanding Your Risk of Catching a Disease

Fortunately, most diseases are not terribly contagious.

We worry about some things, like SARS and Ebola, because they are so deadly, not because they are so contagious or infectious.

Wait, contagious or infectious? Aren’t they the same thing?

To confuse matters, some infectious diseases aren’t contagious, like Lyme disease. And some vaccine-preventable diseases are neither infectious nor communicable. Think tetanus. You may have never thought of it that way, but you aren’t going to catch tetanus from another person. Of course, that’s not a good reason to skip getting a tetanus shot!

To understand your risk of getting sick, you want to understand a few terms, including:

  • infectious disease – a disease that can be transferred to a new host
  • communicable – an infectious disease that can be transferred from one host to another
  • non-communicable – a non-infectious disease which can not be transferred from one host to another
  • contagiousness – an infectious disease that is easily transferred from one person to another
  • infectivity – the ability of an infectious agent to cause an infection, measured as the proportion of persons exposed to an infectious agent who become infected. Although this doesn’t sound much different from contagiousness, it is. The Francisella tularensis bacteria is highly infectious, for example, to the point that folks exposed to a culture plate are given antibiotics or put on a fever watch. Few of us get tularemia though, because transmission is through tick bites, hunting or skinning infected rabbits, muskrats, prairie dogs and other rodents, or inhaling dust or aerosols contaminated with F. tularensis bacteria. So if you get exposed, you will probably get sick, but there is a low probability for getting exposed.
  • incubation period – the time it takes to start having symptoms after you are exposed to an infectious disease. A longer incubation period increases the chances that someone will get exposed to a disease and travel home before getting sick. A shorter incubation period, like for influenza, means that a lot of people can get sick in a short amount of time.
  • contagious period- the time during which you can spread the illness to other people and may start before you have any symptoms
  • quarantine – used to separate people who have been exposed to a contagious disease and may become sick, but aren’t sick yet
  • isolation – used to separate people who are already sick with a contagious disease
  • transmission – how the disease spreads, including direct (direct contact or droplet spread) vs indirect transmission (airborne, vehicleborne, or vectorborne)
  • R0 (r nought) – the basic reproductive number or the number of new infections originating from a single infectious person among a total susceptible population
  • Rn – the net reproductive number, which takes into account the number of susceptibles in a community
  • infectious period – how long you are contagious

Got all that?

How Contagious Is Measles?

If not, understanding how easily you can get measles should help you understand all of these terms.

Measles is highly contagious, which is likely why all of the Brady kids got sick.
Measles is highly contagious, which is likely why all of the Brady kids got sick.

Measles is highly contagious, with a very high R0 number of 12 to 18.

That’s because:

  • the measles virus can live for up to two hours on surfaces and in the airspace where an infected person coughed or sneezed
  • infected people are contagious for up to four days before they have a rash and even know that they have measles, so expose lots of people even if they get put in isolation once they get diagnosed
  • infected people continue to be contagious for up to four days after the rash appears, so can continue to expose people if they aren’t put in isolation

So you don’t need to have someone with measles coughing in your face to get sick. If they coughed or sneezed at the grocery store, on the bus, or at your doctor’s office and then you entered the same area within two hours, then you could be exposed to the measles virus and could get sick.

Why don’t we see at least 12 to 18 people in each measles outbreak anymore?

That’s easy. The definition for R0 is for a total susceptible population. Most folks are vaccinated and protected, so even if they are around someone with measles, they typically won’t get sick.

Still, up to 90% of folks who aren’t immune and are exposed to measles will catch it. That includes infants too young to be vaccinated, kids too young to be fully vaccinated, and anyone who has a true medical exemption to getting vaccinated.

The measles has a very high R0 is easier to see when you compare it to those of some other diseases

 

Infection R0
Diphtheria 6-7
Ebola 1.5-2.5
Flu 1.4-4
MERS 2-8
Mumps 4.7
Pertussis 5-17
Polio 2-20
RSV 3
SARS 2-5
Smallpox 5-7
Varicella 8-10

Why such a big range for some diseases?

These are estimates and you are more or less contagious at different stages of each illness.

Fortunately, in most cases you can just get vaccinated and protected and don’t have to worry too much about them.

More on the Contagious Periods of Diseases