Immunity and Vaccination

According to Tolstoy, patience and time are the most powerful warriors. When it comes to the pandemic, they certainly seem to have been important allies. The time for vaccines has finally arrived. However, we have also been told to not let our guard down. Vaccines are not the only secure gateway, and encompassing a healthy lifestyle is still needed for effective herd immunity and to protect ourselves and our loved ones. While it seems logical, is there science to back up which people are considered vulnerable, even if vaccinated? What other science can we turn to, for protection, in addition to the vaccine?

Several factors influence our response to vaccinations. Of course, the response varies depending on the specific vaccine to be delivered. In general, any factor associated with a weaker immune response is more likely to result in worse outcomes following vaccinations. The opposite is also mostly true. The literature shows that the use of immunostimulants as adjuncts to vaccines tends to improve outcomes.

Of all factors, age seems to have the greatest impact on vaccines. Neonates have an immature immune system and rely on maternal antibodies. Preexisting maternal antibodies inhibits the infant’s antibody responses after vaccinations. Neonates and young infants are less likely to develop an appropriate initial antibody response but are also more likely to see those antibodies wane prematurely. The effect of age at inoculation has been examined extensively with the measles vaccine. A meta-analysis of 20 studies showed that the proportion of infants seroconverting (producing detectable antibodies against the disease) after one dose of measles vaccination increases from 50% at 4 months of age to 85% at 8 months.

It is also well-established that seniors are more vulnerable to infections partly due to a weakened immune response. Seniors also tend to produce a weaker reaction after vaccinations, and antibody levels are more likely to decrease prematurely post inoculation. ,  ,  ,  ,  Genetics also play an important role, with studies showing that different ethnic groups living in similar circumstances have different responses to vaccinations and see different declines in antibodies. ,  ,  Given that these variations are caused by gene polymorphisms and differences in components of the immune response, their effects are variable and difficult to predict.

The comorbidities can have a significant impact on our immune response. For instance, if you suffer from an active infection when getting a vaccine, especially if you are feverish at the time of the inoculation, you are less likely to have a favourable immune response. ,  ,  Patients with autoimmune disorders, such as celiac disease or diabetes mellitus, have also been shown to produce antibodies following fewer vaccinations. Patients requiring dialysis for chronic kidney failure have less favourable responses to immunizations due to factors such as uraemia, malnutrition, and a general state of immunosuppression.

Poor nutritional status is known to negatively affect the immune system. Several abnormalities in immune function have been linked with malnutrition, including deficits in secretory IgA, complement production, gut-barrier function, and T‑cell memory maintenance. Malnutrition reduces the effectiveness of the oral polio vaccine and perhaps others.

What Can Help?

Exercise exerts a positive effect on the immune system. A study looking at the effects of exercise on the response to influenza vaccinations in adults over the age of 62 showed that exercising for at least 20 minutes three times per week increases the antibody response postvaccination.

The microflora in the intestinal tract is an important regulator of the immune system. Studies show that the microflora influences our reaction to vaccinations. A systematic review looked at 26 studies, comprising 3,812 participants, using 40 different probiotic strains with 17 different vaccines. The results showed that probiotics were effective at improving outcomes postvaccination in about half of the studies. Probiotics were particularly effective when combined with oral vaccines. Positive effects were seen with diphtheria, hepatitis A  and B, polio, and rotavirus and influenza  ,  vaccinations.

The literature also shows that immune-stimulating supplements improve outcomes after vaccinations. In animal studies, supplementation with echinacea pre‑ and postvaccination significantly augments the immune response and the production of influenza antibodies. Another study showed that simply adding thyme to the feed of chickens improves their immune response following vaccination against influenza. Animal studies show similar findings with astragalus enhancing the response to an avian infectious bronchitis virus vaccine. Lactoferrin is another supplement with demonstrated immune-stimulating effects. In animal studies, the combination of lactoferrin with immunization against influenza increased the production of antibodies. Studies in mice feed polysaccharides from medicinal mushrooms, ginger, and tangerine peel for 30 days following influenza vaccination had an improved immune response, and the mice were less likely to develop inflammation in the lungs.

Most importantly, human studies in institutionalized elderly patients show that receiving low-dose supplements of zinc and selenium significantly increased the immune response after vaccination, thereby improving the effectiveness of the vaccines.

Conclusion

The lessons are clear: Those with a reduced ability to mount an immune response are more likely to have a poor response following inoculations. Unfortunately, this also means that those most likely to need the protection from vaccines are the ones less likely to obtain it. Healthier lifestyles as well as immunostimulants have potential to be powerful helpers when it comes to improving outcomes following vaccines.