Researchers at the Beth Israel Deaconess Medical Center (BIDMC) have investigated the long-term efficacy of the three available vaccines. Approved for emergency use by the Foods and Drugs Administration (FDA), the Pfizer/BioNTech (BNT162b2) and Moderna (mRNA-1237) vaccines were rolled out across the US in December 2020. The mRNA-based jabs were followed by the single-shot Janssen/Johnson & Johnson vaccine (Ad26.COV2.S) in February this year, giving Americans a wide array of tools to fight the coronavirus.
To date, more than 200 million people across the US have been given one of the vaccines.
However, recent months have raised many questions about the long-term protection offered by the jabs.
Research published in September, for instance, found Pfizer’s vaccine offers waning protection against the Delta variant of Covid within six months of being administered.
Another study published in August found Covid vaccines are only up to 80 percent effective eight months after the jab.
The BIDMC researchers have now pitted the three vaccines against each other and compared the corresponding immune responses after an eight-month period.
In total, the study examined the levels of Covid antibodies, T-cells and other immune products in 61 participants.
The data was collected at two to four weeks after full complete immunisation – the peak time of immunity – to eight months after the jab.
Of the 61 people, 31 received the Pfizer/BioNTech jab, 22 were given the Moderna jab and only eight were given the Janssen jab.
Dan H. Barouch, corresponding author and one of the scientists who helped develop the Janssen vaccine, said: “The mRNA vaccines were characterised by high peak antibody responses that declined sharply by month six and declined further by month eight.
“The single-shot Ad26 vaccine induced lower initial antibody responses, but these responses were generally stable over time with minimal to no evidence of decline.”
According to the team, the Moderna vaccine also produced an antibody response that was higher and more durable than Pfizer’s.
However, all three vaccines demonstrated “broad cross-reactivity” to the SARS-CoV-2 virus, which causes COVID-19.
The findings should give health officials a better idea of how vaccines work in terms of long-term protection.
Health experts have already warned the coronavirus is here to stay, much like the flu.
Dr Ai-ris Y. Collier, the study’s lead author, Even though neutralizing antibody levels decline, stable T cell responses and non-neutralizing antibody functions at eight months may explain how the vaccines continue to provide robust protection against severe COVID-19.
“Getting vaccinated (even during pregnancy) is still the best tool we have to end the COVID-19 pandemic.”
Here in the UK, more than 49.33 million people have already received the first dose of a Covid vaccine.
And more than 45.29 million have received their second dose.
In other words, more than 85 percent of the population aged 12 and older has the first dose, and 78.8 percent has had the second dose.
Globally, more than 6.49 billion doses of the vaccines have been administered.