The current measles outbreak in New Zealand highlights the importance of maintaining high measles, mumps and rubella (MMR) vaccination coverage to ensure that outbreaks remain as rare as possible. Measles is most common in children under one year of age who have not yet been vaccinated. However, changes to the MMR Vaccination Schedule over the years mean that there are still certain populations in the community at high risk of contracting and transmitting measles.
A measles outbreak occurred in New Zealand in December 2013. As of 15 August 2014, 281 measles cases were reported in New Zealand, most of them related to international travel. Measles is a highly contagious viral disease that is characterized by rash and fever and is associated with a number of serious complications. The best protection against measles is vaccination with the combined measles, mumps and rubella (MMR) vaccine. The MMR vaccine was added to the National Vaccination Program in January 1990 and is currently recommended for children aged 15 months with a first dose and a second dose at age four. MMR has replaced separate measles and rubella vaccines that had previously been on schedule since 1969 and 1970 respectively.
To protect against measles, all individuals born on or after January 1, 1969 should receive two doses of the measles vaccine. Anyone who has only received a single measles vaccine prior to the administration of the combined MMR vaccine should receive two doses of MMR to ensure the best protection. There are no safety concerns about getting an extra measles vaccine. People born before 1969 are considered immune from measles as they are presumed to be exposed to foreign-type measles prior to the administration of the measles vaccine.
According to the World Health Organization (WHO), 95% of the world’s population born after the measles vaccine must be fully vaccinated against measles in order to eradicate the disease. Between 1980 and 2012, 81% of two-year-olds in New Zealand received a vaccine containing measles. In 2006 and 2007, 92-93% of children received the first MMR dose, but only 89% received the second MMR dose. These vaccination rates for MMR are not high enough to prevent measles outbreaks. However, the most recent statistics for 2008-2011 are at national coverage rates of 93% vs.94% for the first MMR dose for two-year-olds.
Risk of Measles
Both adults and children can get measles, but the incidence decreases with age. Children younger than one year old are the most likely to become infected with measles, as they have not received the MMR vaccine. However, there was an increase in infection rates among adolescents aged 10-14 years during outbreaks in 2009 and 2011. This is likely due to changes in the MMR vaccination schedule and lower than optimal vaccination rates for the birth cohort born between 1990 and 2000. Measles infection causes lifelong immunity and individuals can only contract the disease once, but sometimes people who have had MMR can get measles. This happens due to insufficient immune response or inadequate vaccination.
Of the 68 measles cases reported in 2012, 40 were unvaccinated, 20 of which were children under 15 months of age. Ten of them received one dose of MMR and seven were individuals who received two doses of MMR. MMR. In the remaining 11 people, the vaccine status is unknown. People who are most at risk of contracting measles are those who do not have the MMR vaccine. There are also people returning from international travel due to the higher risk of exposure in measles-endemic countries and those born overseas in countries where appropriate vaccination is less likely.
MMR vaccination is fully subsidized according to the National Vaccination Program. It is recommended that children be vaccinated at the age of 15 months with a second dose at the age of four. A person born in 1969 or later who has not received two documented doses of MMR needs two doses at least one month apart. MMR vaccine should not be given to pregnant women as it is a live (attenuated) vaccine and pregnancy should be avoided for one month after vaccination and is also not contraindicated in women who are breastfeeding. Vaccination with MMR is very effective and, after one dose of the vaccine, 90 – 95%, 95 – 96 and 90 – 97% of recipients older than 12 months are protected from measles, mumps and rubella, respectively.
After the second dose, almost all recipients are immune to all three diseases. The estimated duration of protection after two doses is lifelong in more than 96% of recipients. However, sometimes some people get measles even after taking two doses of MMR. This may be due to problems with the vaccine, such as improper administration or storage conditions, and decreased immunity over time. In addition, there may be maternal antibodies blocking the vaccine caused by breastfeeding, such as giving doses to babies. If a vaccinated person gets measles, it will likely be less severe.
History of the Measles, Rubella and MMR Vaccine
The history of the measles and rubella vaccine in New Zealand can provide useful information to clinicians about which people are more likely to be not fully protected against measles and rubella. This is why the history of measles, rubella and MMR vaccine in New Zealand is as follows:
1969: Measles vaccine (single dose) was introduced in children aged 10 months to five years.
1970: The rubella vaccine, launched for all four-year-olds, is a single dose.
1974: Age change for measles vaccine up to 12 months.
1979: Due to the low intake of the rubella vaccine at the age of four (especially in boys), the program was changed to the rubella vaccine in 11-year-old girls. (female student rubella vaccination program)
1981: The age change for measles vaccine was 12 – 15 months.
1990: MMR vaccine replaces separate measles and rubella vaccines, introduced for all infants 12-15 months old.
1992: A second dose of MMR was added to the schedule at age 11.
2001: The timing of the second MMR dose was changed from age 11 to age four, and a school-based vaccination program was introduced for all children aged 5-10 years.
What is Measles?
While measles is caused by paramyxovirus, transmission is spread through direct person-to-person contact through oropharyngeal and nasopharyngeal droplets. Also less commonly, since the virus can survive on these surfaces, it can be spread by airborne or contact with infected surfaces, such as door handles and food containers. Measles is one of the most contagious diseases of all. There is an incubation period of approximately 10-14 days after exposure, before symptoms appear. Signs and symptoms are highly characteristic in most people and tend to occur in three stages and these are as follows:
• Fever higher than 38 ° C,
• Weakness, loss of appetite,
Koplik spots (small white spots like salt grains on the buccal mucosa),
The prodromal phase lasting three to four days, when the cough may include 3Cs.
• Common cold (rhinitis),
There is an exanthema (rash) stage characterized by a bright red maculopapular rash that lasts four to five days and is usually not itchy. This rash typically starts behind the ears and then spreads to the face, neck and then to the rest of the body. It is the convalescence phase in which the rashes decrease by leaving a temporary brownish stain on the skin. There are differential diagnoses for measles and they are as follows:
Other causes of conjunctivitis,
For example, drug sensitivities include roseola, enterovirus, adenovirus, and infectious mononucleosis (EBV) infections, scarlet fever, Kawasaki disease, and rubella.
Author: Ozlem Guvenc Agaoglu