Vaccines provide broad protection against COVID-19, scientists say
Vaccines provide broad protection against COVID-19, scientists say

Vaccines provide broad protection against COVID-19, scientists say

A new one examination conducted by Stanford Medicine researchers digs deep into how immunity to SARS-CoV-2 works, and shows that vaccination is likely to provide better and broader protection than natural infection.

The research analyzed the antibody levels in people who had received the vaccine, including some who participated in Stanford’s clinical trials with the BioNTech-Pfizer vaccine, and compared them with those in people who had COVID-19 and were treated at Stanford Medicine in the early days. . months of the pandemic.

“When we compared antibody responses to infection with those from vaccination, we found that infected humans generated variable levels of antibodies, which decreased steadily after infection.” Katharina RöltgenPhD, one of the lead authors of the study, said in a Stanford Medicine news release about the work. “In contrast, the response to vaccination was very consistent – all study participants had a good response with high levels of antibodies, although these also decreased over time.”

I connected with Röltgen and Scott Boyd, MD, PhD, the senior author, to ask them more about their results. Their answers have been easily edited and condensed.

What do you think was the main result of the study?

There were several important findings. One is that people who received vaccines against the virus generate antibody responses that are better at recognizing SARS-CoV-2 variants than those generated by people recovering from SARS-CoV-2 infection. We also found that vaccinated humans have stronger lymph node activity and more of the viral nail protein than patients with the most severe infections. The combination of these factors may be the reason why we see larger and more widespread protective antibody responses after vaccination compared to infection.

Finally, the study also showed that antibody responses to SARS-CoV-2 – whether through infection or vaccination – are significantly biased toward the first viral variants to which you are exposed. This is called “imprinting”, and it means that these are the variants you will respond best to in the future.

Interestingly, all vaccine types in the study had a good response. Was it expected?

We tested antibody responses in recipients of four different vaccines, which fell into three categories of vaccine types. We saw large differences in the overall size of antibody responses, which correlated with how protective these vaccines were during the pandemic. Antibody responses were highest in subjects receiving mRNA vaccines, followed by those receiving AstraZeneca or Sputnik V adenoviral vaccines. They were lowest in recipients of the inactivated virus produced by Sinopharm.

Across all vaccine types, for a given level of antibody response, however, we saw that the vaccinated antibodies recognized viral variants better compared to antibodies from patients who had recovered from SARS-CoV-2 infection. As new viral variants of SARS-CoV-2 continue to emerge in the future, individuals with a wide range of antibodies are expected to have potentially better protection than individuals who have been infected in the past.

The study shows that mRNA from the vaccine can be found in the lymph nodes up to eight weeks after vaccination. What does it mean? Is that something we should be worried about?

An effective vaccine must expose the immune system to the parts of the virus that the immune system must target. The mRNA vaccines do this by directing the body’s own cells to produce the SARS-CoV-2 peak protein. Lymph nodes contain specialized cells that capture foreign proteins, including vaccine components, and display them for a period of time for the B cells that make antibodies. We suspect that these cells may retain the mRNA of the vaccine in addition to the viral nail protein.

We have no evidence that this is a cause for concern, especially given the very low incidence of side effects in people receiving these vaccines.

When SARS-CoV-2 infects a person’s body, it copies its own RNA genome, makes a variety of viral proteins, and damages cells and organs, particularly the lungs. In comparison, the mRNA vaccines have been shown to be very safe and protective against SARS-CoV-2 infection and particularly effective in preventing serious illness and death, even for highly transmissible variants such as omicron. The persistent presence of the tip protein in the lymph nodes where the immune response is organized, as well as some detectable vaccine mRNA there, may help to explain why these vaccines have given strong and protective immune responses.

What would you say to someone who thinks it is better to be infected than to be vaccinated?

If you become infected with SARS-CoV-2, you risk developing serious or fatal disease or long-term health consequences in exchange for less effective future immune protection against SARS-CoV-2 variants. If you are vaccinated, you have a very low risk of serious side effects and your immune system is generally better. Faced with these options, vaccination is clearly the choice that would be better for most people. It is true that the currently approved vaccines are less protective against infection with the omicron variant, but they are still extremely effective in preventing serious illness or death, so it does not change the calculation.

Another important aspect is that if someone gets infected with SARS-CoV-2, they can transmit the virus to other people, including those who may be more vulnerable to serious illness, so that is another reason rooted in social responsibility – vaccination is the more ethical choice in our opinion. Finally, every time someone gets infected, it is possible that the virus can mutate in their body and produce a new, more virulent or infectious variant, which can then be transmitted to others.

Vaccination that prevents or limits infection can help slow down the development of new variants. Likewise, greater production and more extensive global distribution of effective SARS-CoV-2 vaccines may help suppress new viral variants and new waves of the pandemic in the future. Vaccines that can protect against infection and serious illness were quickly sought in the first months of the pandemic, and it is a remarkable achievement that they were developed so quickly and have already protected so many people.

What are you investigating now?

It’s a secret – just for fun! We are investigating how primary exposure to SARS-CoV-2 affects subsequent responses to exposure to different SARS-CoV-2 variants – the “imprinted” phenomenon we mentioned above. In particular, we study individuals who had either previously been exposed to the original Wuhan-Hu-1 antigens, either by infection or vaccination, and then subsequently infected with the omicron variant; or who had a primary infection (and had not previously been infected or vaccinated) with the omicron variant.

Given how widespread omicron has become and how many people have been infected with this variant, it is likely that all future studies will have to take into account the kind of immune responses stimulated by the omicron variant. More generally, it will be more complicated to predict their reactions to new variants as humans acquire different immunological histories of exposure to viral variants through vaccination or infection. This is an important area to study and can help guide decisions about what types of booster vaccines will be most useful in the future.

Photo of Bastian Weltjen

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