The companies that produce COVID 19 vaccine are working on vaccine variants to cover the new strains. For this reason, doctors say that the vaccine against Sars-Cov-2 could end up like the flu vaccine, that is, it should be given every year.
The Modern Company is testing a new version for the vaccine and is using the same volunteers it used last year, when it first tested the serum.
Ian Haydon is one of the patients who last year took part in testing the Moderna coronavirus vaccine, and now he is helping to test a modified version of the vaccine, designed to combat a new, more contagious variant. He recently received a third dose of vaccine.
“It is unclear whether this new modified version of the vaccine will really be needed.” Haydon was quoted as saying by CNN. He is taking part in a study to test not only a modified version of the Modern vaccine to specifically protect against B.1.351 – the South African variant – but also whether a third dose of the vaccine boosts immunity.
After receiving the third dose of vaccine, the patient had some side effects. “I had a fever, chills, a little nausea, a headache“, he said.
Immunologists say this is a sign that the immune system is responding to the vaccine, although people who do not report symptoms also develop an immune response, so the symptoms do not seem to suggest that someone has a better response than someone who does not develop a fever.
Doctors have started testing for a third dose because they are worried that the virus could end up like the flu, which requires a new vaccine every year, because immunity disappears quickly and because new strains appear every year.
Immunologist Scott Hensley, a vaccine expert at the University of Pennsylvania, believes that studies to date show that immunity may last more than 6 months.
The specialist points out that the technology used by both vaccines – both Pfizer and Moderna – ie the delivery of genetic material known as messenger RNA – is very powerful.
„The responses to antibodies caused by these mRNA vaccines are incredibly high. What we know from animal models with other mRNA vaccines that have been tested before is that those antibody responses are incredibly long-lived and do not decrease over time. ”, said Scott Hensley, whose lab has been testing experimental mRNA vaccines for years.
He added that mRNA technology has been studied for many years and used to make vaccines against the flu, Ebola virus and Zika.
The specialist’s claims are supported by the results of researchers from the US National Institute of Allergy and Infectious Diseases, who recently published a study in the New England Journal of Medicine showing that two doses of Moderna vaccine produced a lot of antibodies that decreased just very easy in time.
The vaccine also caused the body to produce immune cells known as T cells and B cells that can maintain defense for years. They found that the vaccine-induced immune response was stronger and less variable than the immune response following a natural infection.
Pfizer vaccine – at least 6 months immunity
On the other hand, a study done for the Pfizer vaccine, published by the company, shows that the vaccine offers at least 6 months of immunity after the second dose.
The data show that the vaccine was 91.3% effective against COVID-19 in an analysis of 927 symptomatic individuals as of March 13. These data are compared with 95% effectiveness reported in the interim results that were announced on November 18, 2020, writes MedScape.
Epidemiologist John Segreti, medical director at Rush Medical College, Chicago, says the 6-month protection offered by Pfizer is very encouraging.
„We are delighted that we can now say firmly that it will take at least 6 months. That is what we can say now, but the protection analysis process is underway“, Said the doctor.
Another Pfizer-BioNTech Phase 3 clinical trial shows that strong immunization after the vaccine persists for at least 6 months, according to Healthline. The researchers found that the vaccine was 100% effective against the development of a severe form of the disease, but at the same time it is 100% effective against African variants of COVID-19.