Vaccine Side Effects: Experts Warn 'Leaky' Vaccines May Make Diseases More Dangerous

Vaccines have been hailed as lifesavers as they protect children against a number of diseases, many of which are lethal. In cases where medication administered offer lifelong immunity, they're are considered "perfect" vaccines but experts have warned that "imperfect" or "leaky" vaccines may bring about more powerful viruses. 

According to a new study published on Monday via PLOS Biology, researcher Andrew Read and his team studied poultry which led to some concerns regarding evolved virus strains. 

When it comes to "leaky" vaccines, immunization is given for diseases like the avian flu or malaria, typically given to livestock. They immunize the individual but aren't able to prevent the spread of the virus itself. There are cases where the diseases still spreads even when the host has already died. 

Those who have been vaccinated may still get sick but it's been observed that they display less severe symptoms. However, the virus itself survives long enough to be transferred to others which then allows it to survive. 

"We now are entering an era when we are starting to develop next-generation vaccines that are 'leaky' because they are for diseases that do not do a good job of producing strong natural immunity - diseases like HIV and malaria," Read said, per Healthline.

As an example, The Washington Post notes that the study looked into Marek's Disease -- a herpes virus that infects chickens. The highly contagious Marek's disease didn't used to be lethal. However, now poultry farmers are noticing more virulent strains in the stock. Vaccinated chickens are protected from the diseases but unvaccinated chickens are becoming much sicker than they used to. 

"Our research demonstrates that the use of leaky vaccines can promote the evolution of nastier 'hot' viral strains that put unvaccinated individuals at greater risk," quoted Relax News (via Yahoo! News) of co-author Venugopal Nair of the Pirbright Institute in the UK. "These vaccines ... allow the virulent virus to continue evolving," he added.

Currently, the unperfected vaccines only exist in vaccines used on animals but researchers have warned that the same could be the case in humans especially as people tackle never before and much stronger diseases. 

Read and his team have recommended that next-generation vaccines be tested thoroughly to prevent the evolution of more-virulent strains in the future.  

What do you think about these reported "leaky" vaccines? Let us know what you think below!