Question

What is the body’s physiological response after receiving an MMR vaccine?

The WHO mentioned that in some parts of the world, we have decreased to less than the threshold set by WHO as that required for herd immunity. Using your best research skills, please find the threshold (percentage) needed for herd immunity for measles, and also explain why it’s important to stay above this threshold.

Answer 1

M-M-R II is a live virus vaccine for vaccination against measles, mumps, and rubella. M-M-R II Vaccine can have some physiological side effects such as:

• Problems with hearing or vision;
• Extreme drowsiness, fainting;
• Redness, swelling at the injection site
• Easy bruising or bleeding
• Sore arm from the shot
• Temporary pain and stiffness in the joints, mostly in teenage or adult women who did not already have immunity to the rubella component of the vaccine

Herd immunity is a mean of protecting people who can't get vaccinated because of their weak immune system and vaccines might make them sick. The required level of herd immunity is different for every disease. To have herd immunity and protect masses, a very high percentage of people in a community needed to be vaccinated. This is called the threshold. The threshold (percentage) needed for herd immunity for measles is 93-95%. In other words, about 93-95 out of every 100 people in a community needed to be vaccinated to prevent its transmission because the measles virus is possibly the most contagious known organism. A study on measles outbreak in 2014-2015 in California, reported very low rates (50%) of measles vaccination in the exposed population. This percentage was far lower than the required threshold for herd immunity to measles, and it put the population at risk of disease. To delay or avert such epidemics it is necessary to maintain a susceptible population immune above some threshold.