The recent measles outbreak in the United States underscores the need for people to get vaccinated not only to protect themselves but also to protect other individuals around them that may be much more vulnerable due to age, health status or being nonimmune. Vaccines are recommended because they have a proven effectiveness in reducing the chance you will get sick or at least need hospitalization if exposed to certain highly contagious diseases. They also pose very little risk from receiving them making the benefits greater than the risk.
Measles is highly contagious with a transmission rate of about 90% from a single. In fact, measles is more contagious than chicken pox which is why most people born before 1957 are presumed to be immune to measles having had the disease before. The vaccine was so successful that it virtually eliminated all native cases of measles in the United States once it became common practice and wide spread.
Today, outbreaks of measles in the United States occur when an international traveler with measles comes into the United States and spreads it to nonimmune contacts. Since a person can spread the disease 4 days before the characteristic measles rash, the infected person is unaware of being contagious. In the United States today there are areas where a significant portion of people go unvaccinated due to various reasons: Unproven concern or misinformation about the vaccine’s risks is the most common excuse but there are also religious and other personal reasons people do not get vaccinated. Since less than 2-3% of people vaccinated remain nonimmune, having everyone get the vaccine would make measles outbreaks in the U.S. almost nonexistence or at least limited to 1-2 nonimmune contacts.
Currently measles vaccines are given as part of the MMR two vaccine series (mumps, measles, rubella) to children at 12-15 months and again at 4-5 years. Adults only need one shot if they were not vaccinated during childhood. Since measles is more common internationally even in the developed countries in Europe and Asia, I do recommend for my patients who travel a lot out of our country to consider a “booster” vaccine above the age of 45 and especially if they were born before 1957 and never received the vaccine or if they are unsure of their vaccination status.
The annual influenza vaccine is not as effective as the measles vaccine since the flu virus can mutate as it traverses the globe. The current manufacturing process takes 5-6 months which makes the vaccine an “educated guess” based on the most common strains during the flu season in Asia of the same year. Last year (2017-18) the Influenza A strain did change and reduced the vaccines effectiveness to about 40% overall. Most years it is much more effective since the flu virus does not mutate significantly very often. However, since the influenza strains are different every year the vaccine is needed annually before flu season which is typically November to late March. The measles virus does not change so the vaccination is only needed once for adults. Children need two because their immune system is not as mature as adults.
Unfortunately, the cold virus mutates frequently and there are over 200 strains of the virus in circulation which makes a vaccination with today’s vaccine technology impractical. Fortunately, catching a cold is more of a nuisance rather than a major health threat. Keeping hands clean and away from the face is the best way to avoid colds.
Other Common Vaccinations for Healthy Adults include:
- Tetanus (Tdap which includes pertussis): Booster every 10 years.
- Shingles (Shingrix): Once at the age of 50-55.
- Pneumonia: Two types, PCV 13 and PCV 23, given one year apart starting age 65. Note sometimes given earlier if at risk due to certain medical conditions.
- Hepatitis A: Two doses given 6 months for international travelers.
For a more complete reference please see this CDC brochure.