Two COVID-19 vaccines – from developers Pfizer-BioNTech and Moderna – have been granted Emergency Use Authorization by the U.S. Food And Drug Administration.
The country’s has begun to roll out the coronavirus vaccines on Monday (December 14), with health-care workers and long-term care facility residents receiving the first doses.
However, realistically speaking, those vaccinated won’t immediately receive immunity from coronavirus. The vaccination requires two doses – each administered about three weeks apart.
“You’re probably not going to achieve the levels of immunity required to prevent infection for 28 days, depending on the vaccine,” says Michael LeVasseur, assistant professor in epidemiology and biostatistics at Drexel University’s Dornsife School of Public Health. He also added that 28 days is roughly a week after the second vaccine dose.
Per CNBC, Health and Human Services Secretary Alex Azar said that about 40 million doses of vaccine will available by the end of this year – which is just enough to inoculate 20 million people. The U.S. has a population of over 300 million. With the vaccines currently available in limited quantities, not everyone will get vaccinated right away.
“This means about 230 million Americans must receive the vaccine. It will take time to produce this many vaccines — and remember the Pfizer and Moderna vaccines are two-dose vaccines, so you need double the number of doses as people. Then the vaccine must be distributed and actually given to people,” Dr. Lena Wen, an emergency physician and visiting professor at George Washington University Milken Institute School of Public Health, explains, via CNN.
The ultimate goal of a vaccine is to harmlessly expose parts of the virus to the immune system, teaching it to recognize the virus as an invader and learn how to fight it. However, researchers are also trying to ascertain if there’s still the possibility that a vaccinated person, who is ideally protected from being infected, could transmit the virus without knowing it.
“For a respiratory germ, like SARS-CoV-2, [COVID-19], the point of entry into the body is through the respiratory tract, predominantly nose and mouth,” says Neal Goldstein, assistant research professor of epidemiology and biostatistics at Drexel University. “An important question is whether the vaccines elicit a strong immune response at these locations, [the nose and mouth], or the immune system destroys the virus elsewhere in the body.”
Health experts caution that we need to achieve herd immunity, where around 60% or 70% of the population develop an immune response to the virus, to be able to stop the virus in its tracks. If the virus can’t find susceptible hosts to infect, it won’t be able to spread easily. In the meantime, health experts and public officials continue to urge everyone to practice more immediate measure to curb the spread of COVID-19, such as avoiding large indoor gatherings, wearing masks, practicing physical distancing and using other public health measures.
“For now, everyone needs to keep wearing masks. There will be small numbers of individuals who cannot get vaccines,” Dr. Wen says. “That’s why the rest of us have to get vaccinated, to protect them. Herd immunity is also called community immunity: The community is getting vaccinated to protect everyone.”
“That’s also why we keep wearing masks, too. We do it to protect ourselves, and to protect others. Remember that even after we get the vaccine, we can spread the virus to others. Also, the vaccine is very effective but it isn’t 100%. The mask still protects you, too,” she continues
