Ask an Expert – Immunizations

Question: What is the good and reliable source for determining what immunizations are recommended for a certain location before travel?

Dr. Maikong Xiong, Family Medicine Physician, gives her answer…

I often use www.cdc.gov, as it is one of the most reliable sources for all vaccination and immunization related questions. The site also sorts relevant information for patient use as well as health care professionals. Another very good resource is the American Academy of Pediatrics, www.aap.org, which is more specific to the pediatric population, but does provide a variety of information in terms of controversies about vaccinating your child.

What are the most commonly recommended immunizations in general? In Southeast Asia? In China? What are common side effects of these?

Vaccinations are typically categorized into one of two groups – “required” vs. “recommended” – for each country or region. Specific vaccination recommendations are made, especially for travel, based on epidemiology studies which look at rates of disease within that region. For Southeast Asia, the recommendations are based on both the prevalence of the illness relative to other region and the availability of vaccinations against those illnesses. Therefore, current recommendations for this area include Hepatitis A, Tuberculosis, Typhoid Fever, Japanese Encephalitis and Rabies – that is of course assuming patients have been previously fully vaccinated and are current on all required vaccines.  Other recommended vaccines include Hepatitis B, Tetanus and BCG.

Are immunizations 100% effective?

No vaccination or drug is 100% effective; one variable which science cannot take into account is the difference in genetics and immune system response. Effectiveness of vaccinations range as low as 60% effective up to 99%, depending on various uncontrolled factors such as age at vaccination, booster vaccinations and timing of boosters. Effectiveness is also dependent on completing vaccination requirement series.

When making a decision to vaccinate, similar to any medical decision, it’s important to weigh the benefits and risks associated with the decision. In this case, the risk of the potential vaccine side effects versus the potential dangers and complications of getting the illness. That risk will depend on one’s health status at the time of travel or vaccination, length of travel and exposures or activities during travel.

What are the common immunizations that are required to be taken in a series? How far in advance should these be taken before travel?

Vaccinations in series include Hepatitis A, Hepatitis B, Japanese Encephalitis and Rabies vaccine. In general, plan at least one-month prior to travel, with a minimum of 2 weeks.

Should a recommended immunization not be received, what are the potential dangers?

Each family will need to make their own decisions about receiving recommended vaccinations based on personal situations, such as length of travel and stay, location of travel and activities and severity of complications without vaccination. In general, most vaccinations carry very similar side effects and risks (fever, sore arm, local site reaction), while the diseases they vaccinate against are very different. Therefore, research the disease you are considering vaccinating against and decide based on probability of being infected, severity of infection and complications and mortality rate.

Are the immunizations in Shanghai imported or are they manufactured in China? Is quality here comparable to elsewhere?

The type of vaccination available is entirely determined by the Chinese government and its CDC. Some vaccinations are only available locally whereas others may have an option of either joint venture (JV) or local. JV vaccines are manufactured abroad and packaged in China. Quality of vaccinations is generally good, since all local vaccines come from the Shanghai CDC. However, take caution that you receive your vaccine from a reputable hospital to ensure their source is reliable.

Are their any immunizations that should be withheld from children, or in general?

In my opinion, children fall into one of the high-risk groups and therefore should receive all required vaccines, as well as be highly considered for recommended vaccines. Exceptions to this are children with highly adverse reactions to vaccine derivatives, those with high fever or severe medical illness at time of vaccination. Keep in mind that all vaccines follow age requirements, so check the schedule and vaccinate accordingly. Every country will have its own specified childhood schedule.

Is it safe to receive several immunizations at the same time?  

That’s a good question, and we do see parents who are often concerned about receiving multiple injections at once. The concern is mainly that the immunizations will overwhelm the body’s immune system and therefore have detrimental effects. However, much research has shown that whether receiving one or multiple vaccines, the burden on the immune system is the same. The conclusion is that the risk of not vaccinating on time is still higher than receiving multiple vaccines, so it’s good to follow the recommended vaccination schedule.

I’ve heard of Japanese encephalitis in China. What is this and how can it be avoided?

Japanese encephalitis is a virus, which is carried by mosquitoes. It can cause severe meningitis, but as with most viruses the symptoms can initially be very vague flu-like symptoms, such as fever, body aches and headache. The virus is more prevalent in rural areas, specifically southern parts of China. There is a live vaccine that is locally made, and given multiple times throughout childhood.

What countries or destinations should be avoided due to exposure to potential health dangers?

In today’s society, the world is increasingly smaller. Diseases that were once only felt to affect one part of the world can easily spread, mainly due to advances in technology in which we can travel so efficiently. If a disease uses humans as a host reservoir, it can be spread before an individual realizes they are infected. Also important are mode and rate of transmission. Therefore, the dangers are not related so much to travel as they are to exposure. The likelihood of infection increases if one is in an endemic region, however, can still be exposed even in your own home country. The good precaution is to be educated and receive immunizations against vaccine preventable illnesses. Secondly, we see that all illnesses have a greater disease burden for those who already have chronic medical problems, as well as certain age groups such as infants, pregnant women and the elderly. Making sure one is as healthy as possible will also guard against having complications from any illness.