Few Studies Say Multiple Vaccines Are Safe, While Plenty Suggest They’re Not
You’re planning a trip to Central Africa so you need a vaccination for yellow fever… your doctor has urged you to get immunized against shingles… and you still haven’t gotten a flu shot this season. Getting all three at once may seem efficient — but not so fast. Multiple simultaneous vaccinations are commonly given to people of all ages, but there’s little evidence that this is safe to do — and in fact, a growing list of research studies indicates it’s actually quite dangerous. Having more than one vaccine at a time increases the risk you’ll have a reaction, possibly a severe one.
There are significant safety concerns regarding multiple simultaneous vaccinations, cautions Vicky Debold, PhD, RN, volunteer director of patient safety at the National Vaccine Information Center (NVIC), a non-profit dedicated to the prevention of vaccine injuries and deaths. We talked about why this may be risky.
Vaccines: Not Just For Kids
In addition to immunizations needed for certain types of travel, many adults assume that the vaccinations they received as children are sufficient — but, in fact, immunity may have faded over the years. Newer and stronger vaccines are available today, and as people grow older they become more susceptible to infections such as flu and pneumonia. The CDC now urges adults age 50 and over to get an annual flu shot (younger adults as well, depending on work, health or lifestyle) … a tetanus-diphtheria or diphtheria-tetanus-pertussis booster shot every 10 years… and vaccinations against pneumococcal pneumonia and varicella (the virus that causes chickenpox).
For the sake of convenience, it has become commonplace to administer more than one vaccine at a time, but unless a vaccine is licensed as a combination it may not have been tested for interaction with other ones — and there are no regulations requiring evidence that administering it with another is safe. Once a vaccination is licensed by the FDA, safety issues are primarily evaluated through reporting of adverse reactions to the government’s Vaccine Adverse Event Reporting System (VAERS, http://vaers.hhs.gov/) and Debold estimates at best 10 percent of adverse effects are reported.
Another issue: Drug company clinical trials (which is how vaccines are studied) typically test them on healthy adults. Little is known about vaccine effectiveness or safety when vaccines are given in combination… especially to older adults who may also be taking other medications or have multiple chronic illnesses, says Debold.
Why Are We Worried?
Several studies highlight the risks of co-administration of multiple vaccines…
- In an NVIC analysis of Gardasil (HPV or human papillomavirus vaccine) reports submitted to VAERS through May 31, 2007, investigators found that people who were vaccinated with Gardasil and the Menactra meningococcal vaccine simultaneously were at least twice as likely to experience serious adverse events, such as seizures and Guillain-Barré syndrome, a paralyzing neurological disorder that has been linked to vaccinations.
- Joint research from the CDC and the FDA found an association with seizures when DTP (diphtheria, tetanus and pertussis) and MMR (measles, mumps and rubella) were administered on the same day or even within 14 days of one another.
- In a study of adverse reactions to vaccines in travelers, researchers found that the rate of local (skin) reactions increased from 45 percent with one injection to 78 percent in people who had more than three.
- In Japan, where multiple vaccination is uncommon, people who had simultaneous vaccinations reported significantly more frequent adverse events than those who had single vaccinations.
Awareness is growing and leading to more research on the problem, which is good news. But there are many nuances that must be explored as well. For instance, many vaccine clinical trials are small and conducted over a short time, sometimes only a few weeks or months — which means not much has been studied about the relationship between vaccines and unexpected and rare events, as well as to chronic illness. Debold believes many more studies of this type are needed.
Multiple vaccinations should be avoided if at all possible, as they may indeed magnify the likelihood of problems. And for all vaccinations, even single ones, Debold recommends…
- Educate yourself about the risks and benefits — websites such as www.cdc.gov/vaccines and www.nvic.org are a good place to start.
- Be aware that there are scientists who believe that the immune system actually benefits from experiencing illness — in a way that is more robust, providing complete and life-long immunity from the disease, compared with the vaccine that may provide only partial and time-limited immunity, Debold explains. Note: For vulnerable seniors, for whom the risk of complications from illness is greater than risk from vaccines, immunization may still be advisable.
- Check on reports of reactions to a vaccine at the government’s Vaccine Adverse Event Reporting System (VAERS) website at http://vaers.hhs.gov/. Also the National Vaccine Information Center at http://www.nvic.org/Report/report.htm, has maintained a vaccine adverse event database, which is based on VAERS data, since 1982.
- If you have a personal or family history of reactions to vaccinations, discuss the risks and benefits of immunization with your physician before coming to a decision, and avoid having multiple vaccinations at the same time. If you have a history of seizures or neurological disorders, severe allergies or immune system disorders, likewise carefully consider which vaccines you need and weigh their risks and benefits.
- Consider rescheduling if you are ill. Reason: You are more apt to suffer a reaction.
- Always try to spread out vaccines by one or two months.
There’s nothing to be lost and likely much to be gained by spacing vaccines out by one or two months or even longer, Debold notes — it’s a way to increase the likelihood you will stay healthy.