What are vaccines?
Vaccines are injections of a weaker form of a virus to alert your immune system to produce antibodies and thus provide protection against a true infection.
Understanding the Immune System
The immune system has two major parts, adaptive immunity, and innate immunity
Adaptive immunity is obtained after being exposed to the disease. The immune system has a memory of the infection and specific antibodies against it are formed rapidly during an invasion by the infective organism.
Innate immunity doesn’t have a memory of any particular condition and is activated without any specificity during any disease.
What are the types of vaccines?
Vaccines can be of two major types, live vaccine, and non-live vaccine.
The live vaccine consists of a live weakened form of the virus. They result in an infection that creates very mild to unnoticeable symptoms. They provide excellent protection against the disease as it actively stimulates the adaptive immune system. However, these vaccines do carry a tiny risk of resulting in the actual disease, especially in people with compromised immunity. Example: BCG vaccine
The non-live vaccine consists of killed organisms. It can never result in disease and will never result in any symptoms. They are not as effective at stimulating the immune system as the live vaccine. However, doctors tend to prefer them to live vaccines due to the zero risk of developing the actual disease. Examples: Combined DTP vaccines against diphtheria, tetanus, and pertussis.
More than 30 years ago, a research group discovered a strange yet incredible phenomenon in Guinea-Bissau in West Africa. Although the focus of the research was on the nutritional status of the community, they also injected all the children of the community with a measles vaccine.
Follow-up on the community a year later produced some intriguing findings. Not only did the measles vaccine provide protection against measles, but it also produced an overall reduction in mortality rate by over 70 percent. As measles only caused 10-15 percent of mortality in the region, so the increased reduction in mortality was a surprising discovery.
Further research confirmed that the improved mortality rate couldn’t be attributed simply to the specific measles protection effect.
This was the first time that the overall reduction in infections by other non-specified organisms was observed for a vaccine. These reduced risk effects were termed as “non-specific effects” of the vaccine.
Further Extensive Research
As of now, the research team has investigated four live vaccines and six non-live vaccines, in Guinea-Bissau and other low-income countries, as well as in Denmark. The findings from all the studies were consistent.
The live vaccines significantly reduced disease and subsequent death much more than provided by the specific protection. In Guinean children injected with BCG vaccine in their first month of life, the overall rate of sepsis and other infections went down by more than one third. Apart from protecting against tuberculosis, the BCG vaccine protected these children from other deadly infections as well.
The vaccines not only activated the adaptive immunity, but they also activated the innate immunity to becoming more potent and active against other infections.
Although the non-live vaccines provided considerable protection against specific organisms, they seemed to have an increasingly negative impact on overall health. In Guinean children, the DTP vaccine had a five-fold higher mortality than children who didn’t receive the vaccine.
If the non-live vaccine were followed by the injection of a live vaccine, the negative effects of the non-live vaccines seemed to become canceled. This pattern has been seen across the globe in many countries.
The future of vaccines
These findings present the need for detailed research on the best vaccine time and pattern of injection of non-live vaccines to be followed by live vaccines. A clearly defined time for each vaccine can significantly reduce mortality and improve the health of children worldwide.