Are you protected from measles? It may depend on your date of birth

CNN –

Nearly two decades after the reported elimination of measles in the United States, the country and the world have experienced a resurgence of cases, including adults who thought they were protected by the vaccine.

Now some are wondering if they are properly vaccinated and still risk getting measles.

In a video posted on YouTube last week, a Detroit rabbi who said he had been "fully vaccinated" nevertheless contracted measles – "three brutal weeks," he said. In another recent case, an Israeli air hostess was unable to breathe alone after a terrible complication of measles: inflammation and swelling of the brain, called encephalitis. Health authorities believe that she also received a vaccine.

"It's so damn contagious, and the way people travel today, it really takes a lot to spread," said Dr. John Cullen, current president of the American Academy. family physicians and family doctor Valdez, Alaska.

"I have never seen cases of measles," he added. "But it's only a matter of time."

Adding to the uncertainty, some adults simply do not know their vaccination status or have long lost their documents, Cullen said. The history of measles vaccine has also raised questions about how people of different ages have been vaccinated: not only has the recommended number of doses changed over the years, but the vaccine itself has also exchange.

He recalled that several years ago, a case of measles appeared in Fairbanks, Alaska – the first case of this state in years. Worried to have been exposed and unsure as to whether they were properly vaccinated, patients to him who had gone there asked for a dose of the vaccine, just in case. (When it is administered within three days of exposure to the virus, the vaccine may offer some protection or mitigate the disease, according to health officials.)

Although Alaska has not seen any cases this year, health officials have issued an alert following an emergency statement in the state of Washington which has confirmed dozens of cases in 2019.

"If we see a substantial increase in the number of measles infections, there will be many more people wondering what their immunization status is," he said.

What are the current recommendations for measles vaccine?

Doctors recommend two doses of the MMR vaccine, so called because it covers measles, mumps and rubella. Doctors administer the first dose between 12 and 15 months, the second between 4 and 6 years.

This recommendation was published in 1989 by the US Centers for Disease Control and Prevention. Previously, a single dose recommendation had been in place since 1963.

Before we received a vaccine, the agency said that 3 to 4 million Americans were infected each year – including 48,000 hospitalizations and 400 to 500 deaths.

In recent years, fewer than 100 cases have been reported throughout the country. But the virus has returned in the years to come, especially in 2019, largely thanks to anti-vaxxeurs, say experts.

"The reason we have hesitation to vaccinate in this country is that people do not remember how bad it was," Cullen said.

A dose of vaccine against two: what is the difference?

If you have been vaccinated with two doses, according to the latest 1989 guidelines, the CDC indicates that you have a 97% chance of being protected against measles. And if these last percent come into contact with the virus, they are less likely to transmit it to others and their disease is often less severe.

One dose is still effective at around 93% to prevent the disease.

"Most virologists only dream of such an effective solution," writes Dr. Anne Schuchat, deputy director of the CDC, the deputy director of the CDC. "Success can lead to complacency, skepticism or even an attack," she added.

The second dose, however, is not a reminder in itself. In research studies, almost everyone has developed signs of immunity against measles with a single dose – and the vast majority of the time, this immunity lasts a lifetime, experts said.

"It was in clinical trials where everything was very strictly managed," said Dr. William Schaffner, an infectious disease specialist at the Vanderbilt University School of Medicine and CDC's vaccine advisor.

But in the real world, despite significant gains against the virus, health experts still found measles outbreaks in children and adolescents who would have been vaccinated with one dose.

A second dose seems to be the case, but the question remains: why did the vaccine fail the first time?

"When it was examined more closely, it was discovered that in the tumult of busy people [medical] In practice, the vaccine has not always been optimally treated, "said Schaffner.

For example, if a doctor or nurse vaccinated several children in a row, they might have left the vaccine out of the fridge too long, which would have caused it to deteriorate. Even placing it in the door of a refrigerator, which is slightly warmer than the interior, may in some cases be enough to degrade the temperature-sensitive vaccine, he added.

It's less of a threat now that health care providers are more knowledgeable about how to handle the vaccine. In addition, we opted for single-dose vials from multi-dose vials that could have been left out between injections, Schaffner said.

Nevertheless, the administration of two doses has allowed the health systems to "fill" a small percentage of children for whom the vaccine was not used for the first time.

"This is a wonderfully American solution: we will double the cost of the vaccine program to protect this small group of children from measles and its complications," Schaffner said. "This strategy has worked brilliantly and has been adopted in developing countries.

"And the only way for this to be sapped, is when the kids are not vaccinated."

What vaccine did I receive?

If you were born before the 1960s, you may have never been vaccinated against measles because it was assumed that you had already been exposed to the virus. In fact, the CDC says most people born before 1957 do not need the vaccine because "before the vaccines were available, almost everyone was infected with the measles, mumps, and measles virus. rubella during childhood ".

Then, in 1963, two types of measles vaccines were introduced: one was "killed" and the other was "live attenuated". The difference is that the first inactivates the measles virus, while the other has a weakened form.

The killed vaccine, which was administered to about 600,000 to 900,000 people, was himself killed in 1967 "because it did not protect against measles infection," says the CDC. The agency also recommended that people vaccinated or not knowing which of the vaccines they received in those years are being vaccinated again.

The following year, in 1968, a new version of the live vaccine arrived on the market. He was as effective as his living predecessor, attenuated and even surer than the first, as he had been weakened further. It is still used today, in combination with mumps and rubella vaccines, and has been available since 1971.

Experts say that many middle-aged adults who were vaccinated at first do not know which one they received. Whether one has received the "live" or "killed" vaccine was not always documented, Schaffner said – and these days, these decades-old records might be untraceable.

"At the time, the profession was not as nuanced about the administration of vaccines," Schaffner said.

In addition, neither the CDC nor any national organization has kept a vaccination record. The different states have vaccination records, but these did not arrive until later. For many Americans, "Existing records are those that you or your parents have received when administering the vaccines and those listed in the medical record of the doctor or clinic where the vaccines were administered. ", according to the CDC, which recommends Do a search among baby books, school records and previous employers who were able to collect such information, such as the army.

But many adults will not be lucky.

The older archives "simply do not exist anymore because the doctors have closed their practice, they have retired, they are gone," Schaffner said. "It would be almost impossible to actually resurrect these records."

What do the experts recommend?

If you have received two doses of MMR or if laboratory results have shown immunity or prior measles infection, the CDC tells you that everything is ready.

If you have received a documented dose of the live vaccine and your risk of exposure is not high, the agency believes this is also appropriate.

Those at higher risk, who are recommended by the agency to take two doses, may be working in the health sector, traveling abroad, or more likely to be affected by an outbreak.

Some people can not get vaccinated at all or have to wait – for example, people with weakened immune systems and babies too young to respond to the vaccine.

Born before 1957 and does not work in the health sector? The CDC considers that "proof by presumption" that you are immune from being exposed to the virus in a pre-vaccine era.

But what if you do not have written documentation on the correct vaccine? For those who are not sure, the CDC says that you can simply roll up the sleeve for another dose or two.

"The MMR vaccine is safe and there is no harm in taking another dose," the agency said.

Cullen, however, acknowledged that the number of people uncertain about their immunization status could be very high.

"If we had an epidemic in our area, would we have enough MMR to distribute to those affected?" he asked himself. "Probably not, in these circumstances.Unfortunately, it's kind of the new reality that we face."

There is also a blood test that doctors can use to check for immunity, but obtaining the results may take some time, he added.

For the general population, Schaffner stated that the blood test was "expensive, impractical and rarely produced an actionable result".

"The juice is not worth it," he says. "The way to prevent these elderly people from contracting measles is to make sure all children are immunized."

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