Vaccine Palooza

Today, we look at the efficacy of three widely-available vaccines, and we start with a close look at the flu vaccine, which turns out to be an extraordinary lifesaver.

Every year, influenza typically kills between 4,000 and 20,000 Americans––though the death toll for the 2017 to 2018 season was estimated at 80,000, making it one of the deadliest in the last half century. Most hospitalizations and 90 percent of flu-related mortality occur in those age 65 and older (and most over the age of 75). Mortality rates for the flu at ages 75 and older are 50 times higher than those below age 65. Nonetheless, the CDC recommends everyone over the age of six months get a routine annual flu shot every year––if for no other reason than to help prevent transmission to the more vulnerable. The cruel irony is that older adults—the ones who need protection the most—acquire less robust protection from flu shots, due to waning immunity with age.

Depending on the season, vaccination typically reduces the risk of getting the flu by about 40 to 50 percent. So, in healthy adults, we can say with moderate certainty we can decrease the risk of getting it from like 2 percent each year down to just under 1 percent. Among older adults, even if you get a similar relative risk reduction—from 6 percent down to 2.4 percent—since the risk is higher and the consequences greater, the absolute benefits are greater too.

In the Northern Hemisphere, the flu season can start as early as September, and go as late as March. The problem with getting vaccinated too early in the season is that immunity might wane before the season is over, especially in older adults. So, it might be good to wait until October. But getting it at any time throughout the season is preferable to not getting vaccinated at all.

Yes, the influenza vaccine can cause Guillain-Barré syndrome, an autoimmune attack on your nerves that can leave you paralyzed for weeks—but so too can getting the flu. There are may be one to two additional cases of Guillain-Barré per million vaccinations, versus about 17 extra cases per million contacts with the flu virus. So, you’re much more likely to be temporarily paralyzed by the flu than the flu shot. But since it takes vaccinating about 30 older people to prevent one case of the flu, getting vaccinated would still, in expectation, raise your overall Guillain-Barré risk. But the reason flu shots are recommended is not to lower risk of some obscure autoimmune syndrome, but to reduce the common, and potentially devastating, impacts of the flu that extend well beyond just the respiratory infection.

In the week following a confirmed flu infection, the risk of having a heart attack shoots up six-fold. The inflammation of infection can destabilize atherosclerotic plaques, constrict arteries, and make the blood more liable to clot. So, might flu vaccinations save lives in more ways than one? That’s why indirectly, the flu may kill up to three times more.

Those who get their flu shots are indeed less likely to die from cardiovascular disease in a given year, as well as all causes put together. In other words, those who get regular flu shots live, on average, longer lives. But, who disproportionally gets flu shots? White, married, nonsmokers of a higher social class, with higher education, higher incomes, and health insurance. You can’t tell if it’s truly cause-and-effect until you put it to the test.

There have been four randomized controlled trials—flu shots versus placebo shots—in those with pre-existing heart disease, and overall, those who got the real shots had a 56 percent lower chance of dying from cardiovascular disease, and a 47 percent lower chance of dying from all causes put together. So, flu shots really can be an extraordinary life-saver. Whether the observational data showing fewer deaths across the board—even among those without pre-existing heart disease—similarly pans out is, as of yet, unknown. But, for secondary prevention the randomized controlled trials showed even more protection than the observational studies hinted at.

Given the benefits, overcoming vaccine hesitancy should be as simple as correcting misinformation. But sadly, debunking vaccine myths can actually backfire. Busting the myth that inactivated flu shots (the type given to older adults) can give you the flu surprisingly makes people even less likely to get it. Similarly, correcting the falsehood that MMR vaccines cause autism, or that pertussis vaccination causes as many side effects as people think, paradoxically makes people less inclined to vaccinate. The researchers conclude “correcting vaccine myths may not be an effective approach to promoting vaccination.”

In our next story, we’ll look at how the pneumonia vaccine significantly reduces the risk of pneumococcal pneumonia in people 65 and older.

Vaccines are considered one of the greatest public health achievements of the last century, having eradicated smallpox, a scourge that killed hundreds of millions of people, and greatly reducing other major diseases, such as measles and polio. To this day, vaccines are estimated to save millions of lives a year.

More than 90 percent of U.S. children get common childhood vaccinations, such as polio or their measles, mumps, and rubella shot. But most adults fail to get their full complement of recommended adult vaccinations. Assuming you got all your childhood vaccinations (and aside from any emergent pandemic needs), the CDC recommends all healthy adults get annual flu shots, tetanus boosters every ten years (though the World Health Organization doesn’t think this is necessary), shingles vaccination at age 50, and pneumonia vaccine at age 65. Certain groups need others, such as a hepatitis B series for healthcare workers or men who have sex with men. Ask your medical professional for a personalized schedule.

How safe are vaccines? In a systematic review and meta-analysis, the RAND Corporation screened more than 50,000 citations, and concluded that routine vaccinations can be considered safe, with only rare serious adverse effects, such as severe allergic reactions in one to 10 in a million, and transient autoimmune syndromes Guillain­ Barré and immune thrombocytopenic purpura in one to three in a million, and 10 to 30 in a million for flu shots and MMR vaccines, respectively. Of course, any adverse events should be weighed against any protective effects that vaccines may provide. In my last video, I talked about the effectiveness of flu vaccines. What about pneumonia vaccines?

“Pneumonia may well be called the friend of the aged,” wrote the “Father of Modern Medicine,” Sir William Osler, over a hundred years ago in 1898. “Taken off by it in an acute, short, not often painful illness, the old man escapes those ’cold gradations of decay’ so distressing to himself and to his friends.” The thought was that pneumonia mercifully killed those that would soon die anyway from potentially a more protracted, painful illness. But these days, healthy older adults hospitalized for pneumonia are not significantly more likely to die in the subsequent two years than younger adults in the same situation. Because of comorbidities at older ages, though, pneumonia is the fourth leading cause of death in the world, and the ninth leading cause in the United States.

The most common cause of community-acquired pneumonia (as opposed to hospital-acquired) is a bacteria known as pneumococcus (or Streptococcus pneumoniae-eye). In addition to pneumonia, pneumococcus can cause inner ear infections, sinusitis, or pinkeye. It gets serious when it starts to invade the bloodstream, which can result in meningitis (infection of the brain), endocarditis (infection of the heart valves), or sepsis (a life-threatening organ dysfunction caused by blood poisoning).

Thankfully, we have vaccines against pneumococcus. The first was developed over a century ago, but they fell out of favor after penicillin was discovered, thinking antibiotics would eliminate the threat. Unfortunately, these days up to 40 percent of these kind of streptococcal infections are resistant to at least one antibiotic, and despite our miracle drugs, mortality rates of invasive pneumococcus in the elderly remain around 15 to 30 percent. However, randomized controlled trials have found that pneumococcus vaccines reduce the risk of those 65 and older getting pneumococcal pneumonia by 64 percent, and, even more importantly, your risk of invasive pneumococcal disease by 73 percent. Like the flu vaccine, population studies have found that pneumonia vaccines can reduce the risk of both heart attacks and the overall risk of dying. But unlike the flu vaccine, there aren’t randomized controlled trials to confirm these bonus benefits.

Finally today, we’ll discover how the new shingles vaccine compares with the previous one.

Adult vaccination can be thought of as a cornerstone of successful aging, but a major issue hampering the uptake of shingles vaccination is the lack of awareness of the disease. Shingles is caused by a reactivation of the chicken pox virus later in life. After your body beats back chicken pox, the virus hides in waiting in your spinal cord, waiting for an opportunity to strike back. When it does, the virus can surge forth, traveling along the path of a nerve branching off the spinal cord, wrapping around one side of the body to the front, producing skin blisters along the way in a characteristic belt-like pattern that does not cross the midline in front. (Both shingles and the name of the virus, zoster, are from the Latin and Greek, respectively, for “belt”).

The blistering rash can be intensely painful and leave scarring or discoloration behind but usually disappears in a few weeks on its own. However, approximately 30 to 50 percent of people suffer “postherpetic neuralgia,” persistent pain that can last for a year or more, that sometimes can be debilitating. Usually, it affects nerves around your trunk, but in 10 to 25 percent of cases, it can erupt across your face, which can lead to permanent facial muscle weakness, hearing loss, or blindness. As if that’s all not bad enough, having shingles as much as quintuples your odds of having a stroke over the subsequent few weeks, a risk that gradually declines over the following six to twelve months.

It’s surprising more people don’t know about it, since the lifetime risk of shingles is 30 percent––meaning nearly one in three will get it sometime in their lives. Young adults only have about a one in 1,000 chance of getting it every year, whereas in older adults that climbs to closer to one in 100 each year. That comes out to a million cases of shingles every year in the United States. Thankfully, there is a shingles vaccine.

The first became available in 2006, using a live weakened strain of the virus. The efficacy was only about 50 percent, and couldn’t be used in immunocompromised individuals, such as those with HIV or on immunosuppressive drugs, such as many on chemotherapy. Thankfully, in 2017, a recombinant shingles vaccine was approved, with a 90 to 97 percent efficacy for preventing an outbreak. It requires two separate injections 2 to 6 months apart and is expensive ($280), but covered by Medicare and most private insurance plans. It also can cause transient systemic symptoms, such as muscle aches, fatigue, headaches, or fever and chills serious enough to interfere with everyday activities about 10 percent of the time. But the new vaccine is considered so much more effective that it’s recommended for everyone starting at age 50, even if you were previously immunized with the old one. Given that the new vaccine is only about five years old, longer-term safety and efficacy data are still coming in, but, so far so good. As soon as I turned 50, I lined up for mine.