More than 559 million doses of vaccines have been administered in 141 countries, making it the biggest vaccination campaign in human history, according to data collected by Bloomberg.
Despite this massive vaccination campaign, the number of daily cases has been increasing. According to the pandemic data website Worldometer, 441,868 new cases were recorded worldwide on Monday.
This growing number of breakthrough infections that occur when fully vaccinated people get infected by the virus from which the vaccines were designed to protect is no cause for concern, reports The Atlantic.
According to BBC Future, there are two types of immunity people can achieve with vaccines.
One is “effective” immunity which can’t prevent the virus from getting into the body. However, it can stop the pathogen causing serious disease.
Another form of immunity is “sterilizing” immunity, which can thwart the entirety of the virus by preventing transmission.
But most vaccine research centred around the aspiration of eradicating the virus has not been successful.
The existing Covid-19 vaccines in the US are found to be powerful weapons against serious disease, hospitalization, and death.
However, there is no conclusive evidence to claim that the current Covid-19 vaccines can completely prevent transmission.
Efficacy, a figure usually measured in clinical trials, doesn’t always translate perfectly to the messiness of the real world, where there’s immense variability in how, when, where, by whom, and to whom shots are administered.
And it can be difficult to distinguish the impact of inoculations from that of measures such as lockdowns and mask mandates.
The vaccine’s performance in the real world is usually tracked by a separate measure, which is called “effectiveness.”
Studies rigorously examining vaccine effectiveness are challenging, but early data suggest that the Pfizer-BioNTech and Moderna shots are living up to their initial hype.
The Moderna and Pfizer-BioNTech jabs reduce, on a population scale, the risk of disease by about 95%; Johnson & Johnson’s clocked in at 72% among Americans.
However, a vaccine with a recorded efficacy of 95% doesn’t give everyone who’s vaccinated a 5% chance of getting sick. Not all of those people will even encounter the virus.
The key is how vaccination changes the outcome for those who are meaningfully exposed: Among 100 individuals who might have fallen ill without the vaccine, just five symptomatic cases might appear, reports the Atlantic.
The emergence of new Covid-19 variants has been a subject of concern as the current vaccines that are being administered were all designed around the original coronavirus variant. “The concerns regarding breakthrough cases arise when more variants exist,” Saad Omer, a vaccine expert at Yale, told The Atlantic.
However, these troublesome variants have yet to render any of the current vaccines obsolete.
According to The United States Centers for Disease Control and Prevention (CDC), a team at the CDC is tracking breakthroughs and will soon start reporting case counts, as well as any patterns related to where, or in whom, these infections are occurring, Martha Sharan, a CDC spokesperson, told The Atlantic.
According to her, details like these are vital and can help experts figure out why post-vaccination infections happen, and how they might be stopped.
There’s something counterintuitive about breakthrough cases: The more people get vaccinated, the more such breakthrough cases there will be. But the rate at which they appear will also decline, as rising levels of population immunity cut the conduits that the virus needs to travel.
This is called herd immunity, which is the indirect protection from an infectious disease that populations acquire when enough people are immune, and which eventually drives down cases to somewhere near zero.
