This week, the Biden administration announced that it will begin providing COVID booster injections to most Americans eight months after receiving the second dose of Pfizer or Moderna’s messenger RNA (mRNA) vaccine. After obtaining the approval of the U.S. Food and Drug Administration and the Centers for Disease Control and Prevention Vaccine Advisory Group, people will start receiving boosters on September 20. Health care workers and nursing home residents will be the first eligible people.
When the news was released, scientists had been arguing whether such boosters were needed, who should get them, and when they should be used.It was made less than a week after the CDC recommendation People who are moderately or highly immunocompromised Additional injections should be received because there is evidence that they may not respond adequately to the two doses.The latest recommendations are based on Israel, vaccine manufacturers and Some US Learn It shows that the vaccine-induced immunity to COVID weakened after six months-and that the vaccine is not as effective as against early strains in preventing mild or moderate disease caused by the infamous Delta variant of the coronavirus. However, two doses of mRNA vaccine still seem to provide excellent protection against serious illness and death.
President Biden’s chief medical adviser, Anthony Fauci, said at a White House press conference on Wednesday: “If you wait for something bad to happen…, you are far behind your true full response capacity. …..”. “You want to be ahead of the virus.”
Not all experts believe that most healthy people need boosters. The World Health Organization says it is unethical for rich countries to distribute vaccines to people who have been vaccinated when so many people around the world have not yet received a dose of the vaccine. But the Biden administration defended its decision, saying that the U.S. government should not choose between protecting its citizens and protecting the rest of the world. At the same time, several experts believe that, compared to booster injections for people who have been vaccinated, getting more vaccines for Americans who have not been vaccinated so far is a more effective strategy to protect the population.
Scientific american Asked by Shane Crotty, a virologist and professor at the La Jolla Institute of Immunology, and Céline Gounder, an infectious disease expert and epidemiologist at New York University and Bellevue Hospital in New York City, and a member of the Biden-Harris Transitional COVID-19 Advisory Committee Dao, on whether to strengthen injections and other issues.
[An edited transcript of the interview follows.]
Do we need to intensify injections? If so, who needs them most?
typical: The data clearly shows that even with the Delta variant over time, the vaccine still has a high degree of protection against serious illness, hospitalization, and death. We have not seen that the protection measures against hospitalization and death are weakening. What we are seeing is decreased immunity against the infected Delta variant.
Obviously people who should receive additional doses include highly immunocompromised people: solid organ transplant recipients, AIDS patients, people taking highly immunosuppressive drugs for cancer or autoimmune diseases-these people respond more to vaccination. small. Some people will respond to additional doses, but not all. In addition, people in nursing homes, we have seen breakthrough infections go bad and lead to serious illnesses and deaths. Caregivers who have not been vaccinated may introduce the virus to nursing homes. It makes sense to provide additional doses to residents of nursing homes, but giving them to caregivers may have a greater impact. In addition, there is really no clear data to support the provision of additional doses to the public in the United States.
Crotty: It boils down to the word “need”. People have different meanings. The data of the past month has created enough uncertainty for Delta Air Lines and how long the protection will last. I think the government’s decision to adopt a “safer than sorry” approach to boosters is a reasonable approach. You don’t want to make a decision too late.
People with absolutely weakened immune system need boosters. Highlights from May, June and July indicate that many people with weakened immune systems do not respond well to two injections, but respond better to three injections. There is now a clinical trial that clearly shows that the third dose is helpful for certain types of immune-compromised people.If people have good T cells [a type of immune cell] After one or two doses, they had a good antibody response to the third dose. Should we provide boosters for people over 80? This makes perfect sense. It has a small population and we know that they are at very high risk. What about people over 70, 60, 50? These are real policy decisions.
How good is the immune response produced by the vaccine?
CROTTY: It seems that the vaccine will produce high-quality immune memory.There is a piece of paper in it science Last week at Modern vaccine It showed antibodies within six months after the second vaccination, and did not drop that much. We published the first data on T cell memory after six months of mRNA vaccine (low-dose Moderna). Within 1 to 6 months after vaccination, T cell memory hardly changes. It may last more than a year. Look at the data from England-they have a large number of deltas, and the vaccine has played a good role in it.Compared with the winter wave, there is a huge difference in the number of hospitalizations and deaths in the delta wave [when the Alpha variant first identified in the U.K. was widely circulating]. Do you need a booster? Not applicable to hospitalization or death.
Will the booster work? Yes, Moderna’s clinical trial data and Pfizer’s data indicate this. They will increase antibody titers. But do we need them? uncertain.
What do you think of the Israeli data, which show that vaccine immunity has decreased significantly over time?
CROTTY: In terms of vaccine reduction, Israel’s data is the best.But the Israeli official did not announce any news [in a scientific journal]. I got inspiration from epidemiologists. Confounding factors are a big problem.Israel has many [apparent] Vaccine efficacy issues in February and March. They finally published a paper showing that the vaccine works well.Now it seems to be down [in effectiveness] And it may drop significantly. It is possible that we will never know.
typical: There is indeed a problem with Israel’s data. They are confused by age and other factors. They need to be shared, not in PowerPoint slides; the original data needs to be shared. I will not make any decisions based on Israeli data.
Laboratory data also poses problems. The so-called neutralizing antibodies are the best correlators for protection. But when you measure them after six months to a year, it is not clear. If you have antibodies to every infection you have ever had, your blood will become silt. If you see the disappearance of immune cells and T cells called memory B, that is another problem. However, you expect the antibodies to decline.
Should people vaccinated by Johnson & Johnson get a booster?
CROTTY: In my opinion, now is the time for the second dose of the Johnson & Johnson vaccine. Delta variants spread much faster than previous strains. The available data indicate that immunity to Delta is weakened. A huge Johnson & Johnson COVID-19 vaccine study has just been released, including Delta variants-a study of 500,000 people in South Africa. The vaccine provides 93% death protection and 71% Delta hospitalization protection. This seems to be consistent with a reasonable dose of a booster of Johnson & Johnson vaccine. [Editor’s note: This answer was adapted from severalTwitter threads Crotty referred us to.]
typical: We should soon obtain data from a clinical trial investigating the low-dose and high-dose, and single-dose and two-dose regimens of Johnson & Johnson vaccine. These data will help guide recommendations for providing additional doses of vaccine to people who have already received a dose of Johnson & Johnson vaccine.
Should we mix and match vaccines—for example, an adenovirus vaccine, such as AstraZeneca or Johnson & Johnson, plus an mRNA vaccine?
CROTTY: For people who have been vaccinated with viral vectors [such as the AstraZeneca or Johnson & Johnson vaccines]Obviously, the subsequent dose of mRNA is better than the second dose of AstraZeneca, and it is also better than the two doses of mRNA.There are data to support the hybrid vaccine can be traced back [at least] 20 years-this is called heterogeneous prime number-boost. The order is important. I won’t get Pfizer, then Johnson & Johnson.But you can consider buying Pfizer first, then protein vaccine [a vaccine that contains fragments of SARS-CoV-2 proteins, such as one made by Novavax, which has not yet been authorized in the U.S.].
typical: We need to talk more about heterologous initiation-enhancement: adenovirus vaccine followed by mRNA or adenovirus followed by protein vaccine-we are probably moving in this direction. We should also consider intranasal inhaled vaccines.Those will better activate mucosal immunity [immunity in the nose and upper respiratory tract].
Will the third injection have side effects? If so, how serious might they be?
GOUNDER: Maybe more of the same: mild fever, pain, fatigue. But not everyone will have these.
With so many places in the world still unvaccinated, is it ethical to vaccinate people with booster shots?
CROTTY: I think this is a wrong dichotomy. The vaccines are about to expire; you will not move them. In the United States, the best situation is to vaccinate everyone who has not been vaccinated. This is much better than handling boosters.this Math is not even close.
typical: Obviously, just giving people an extra dose will bring diminishing returns.By reducing transmission in the community, you can have a greater impact [by vaccinating the unvaccinated].
How often do we need boosters? Is it just one, or does it need one every year like a flu vaccine?
GOUNDER: I really hate the word “booster” because it means vaccinations every year. I think the COVID vaccine is most similar to the hepatitis B vaccine. We don’t get the hepatitis B vaccine every year. It is indeed optimizing the dosing schedule-how many doses and what intervals. I don’t think it will be once a year. I think we are watching it become an endemic virus. The idea is to convert it from something that would hospitalize or kill you to something like the common cold.