People who have been infected with the new coronavirus still need to be vaccinated?
To answer this question, we should consider it from the following two aspects:
Can natural infection with the new coronavirus produce sufficient protective immunity?
We know that people with infectious diseases such as smallpox and measles can obtain long-term or even lifelong immune protection as long as they are infected once.
According to research on the dynamics of protective neutralizing antibodies, the immunity generated by infection with smallpox virus can even last for up to 260 years.
Therefore, as long as you have been infected with these infectious diseases, you usually no longer need to get vaccinated against them.
However, for other infectious diseases, natural infection cannot induce sufficient or lasting immunity, and targeted vaccines are often still required to prevent reinfection.
For the pandemic coronavirus, can natural infection induce immunity enough to avoid reinfection?
is currently lacking sufficient evidence.
However, as early as the beginning of the pandemic, scientists believed that infection with the new coronavirus does not produce complete and lasting immunity, and repeated infections after infection are inevitable.
is widely circulated that the saying that the new crown pandemic will turn into an endemic epidemic is derived based on this understanding.
In August 2020, after Hong Kong, my country reported the world's first reinfection case, this statement was initially confirmed; although, it is generally believed that reinfection of the new coronavirus is a rare event.
However, a study from a nursing home in the United States published in February 2021 showed that the incidence of reinfection among the elderly within one year was as high as 40%.
Although this is the largest epidemiological survey on reinfection to date, the number of studies is small (5/12 cases) and is limited to elderly people in nursing homes, which is generally not very evidence-based.
In addition to the reinfection rate, another indicator to measure whether natural infection can produce protective immunity is the study of neutralizing antibody dynamics.
So far, there is also insufficient evidence in this regard.
To date, the largest study in this area was published in March 2021. A study from Denmark based on a community population of more than 500,000 showed that natural infection can produce 80.5% of the protection from reinfection within one year.
But among the elderly aged 65 and above, this protection is only 47.1%.
That is to say, using neutralizing antibodies as evaluation indicators, natural infection cannot produce sufficient immune protection and still requires vaccination.
Ideal solution for intensified vaccination after natural infection
So far, limited evidence shows that naturally infected with the new coronavirus does not produce sufficient immune protection, and there is still a need for vaccination.
However, the new crown vaccine is a scarce public health resource after all, and vaccination also has some potential side effects.
What kind of vaccination plan should be adopted for people infected with the new coronavirus to be more efficient?
Since most of the new crown vaccines currently approved for use require 2 doses, do people with natural infection also need to receive 2 doses?
latest published in the journal Nature Medicine study from the Sida Senai Medical Center in the United States provides us with preliminary evidence.
Researchers surveyed 1,090 medical staff in the medical system that received Pfizer BioNTech's COVID-19 vaccination.
survey content includes previous coronavirus infection and all symptoms before and after vaccination.
In addition, all medical staff under investigation received blood antibody tests within three days before and after the first vaccination, 7 to 21 days after the first vaccination, and 7 to 21 days after the second vaccination, to evaluate the vaccine-induced immune protection response.
35 people who have been infected with the new coronavirus have received a single dose of vaccination, and 228 people who have not been infected have received two doses of vaccination.
Results, there was no difference in blood COVID-19-virus-specific antibody levels and inoculation responses in the above two groups.
After the first vaccination, those who had been infected with the new coronavirus had more prominent side effects, while the side effects symptoms between the two groups were similar after the second dose of vaccination.
Researchers believe that people who have been infected with the new coronavirus previously only need to receive one dose of Pfizer BioNTech vaccine to produce the same immunity as those who have not been infected receive two doses of the vaccine.
From this, the researchers concluded that people who have never been infected with the new coronavirus should receive two doses of vaccination, while those who have been infected only need a single dose of vaccination, which is an efficient and reasonable vaccination plan.
Summary:
Based on currently limited evidence:
- People who have naturally been infected with the new coronavirus still need to receive vaccination;
- For the common two doses of vaccine, people who have never been infected have received two doses of vaccination, and people who have been infected only need a single dose of vaccination to produce the same immunity.
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