Events of the last week have presented people with quite a big and confusing contradiction which made Kenyans question the entire Covid vaccination process.
Days earlier, Meru governor Kiraitu Murungi was seen by millions of Kenyans taking the Covax vaccine in front of cameras.
Days later, what they heard thrust them into confusion. It was announced on Radio and TV that the Meru governor had contracted the Corona virus.
This was perplexing; how can the governor contract the disease yet we saw him take the vaccine?
Then soon afterwards came the explanation by the Health CAS which was even more puzzling. In not so many words, Dr. Mwangangi said that, one, getting the Covid vaccine doesn’t prevent you from contracting the disease, and two, getting the Covid vaccine doesn’t stop you from transmitting the disease.
Naturally, the next question people asked was the obvious one; why then should we bother getting the vaccine if it won’t make us immune to the virus?
In very simple words, free of any medical jargon, here is what the doctor meant;
most vaccines don’t fully protect against infection, even if they can block symptoms from appearing. As a result, vaccinated people can unknowingly carry and spread pathogens. Occasionally, they can even start epidemics. There are two main types of immunity you can achieve with vaccines. One is so-called “effective” immunity, which can prevent a pathogen from causing serious disease, but can’t stop it from entering the body or making more copies of itself. The other is “sterilising immunity”, which can thwart infections entirely, and even prevent asymptomatic cases. The latter is the aspiration of all vaccine research, but surprisingly rarely achieved.
Of course, the next obvious and logical question would be, what kind of immunity does the Covid vaccine offer?
“In a nutshell we don’t know, because they’re too new,” says Keith Neal, a professor emeritus of epidemiology at University of Nottingham.
So far, the available Covid-19 vaccines have not been judged primarily on their ability to prevent transmission – though this is now being evaluated as a secondary endpoint for many of them. Instead, their efficacy was assessed by whether they could prevent symptoms from developing.
“This means that we set our targets kind of pragmatically,” says Danny Altmann, professor of immunology at Imperial College London.