Should you get a COVID-19 booster shot now or wait until fall? Two immunologists help evaluate options – The Conversation

While COVID-19 vaccines continue to emerge very effective In preventing hospitalization and death, it has become clear that the protection offered by current vaccines fades over time. This requires the use of booster shots Safe and effective in boosting the immune response against the virus and extending protection.

But when to get the first or second reinforcement, and which one to choose, are open questions. Many people find themselves unsure whether to wait for new and updated formulations of COVID-19 vaccines or to mix and match batches of the original vaccine strains.

Uses SARS-CoV-2, the virus that causes COVID-19 Spike Handle Protein To enter cells and cause infection. Both current and upcoming vaccines rely on spike protein mimics to stimulate the immune response. However, each type of vaccine delivers spike protein to the immune system in different ways.

as such Immunologists Inflammatory study and Infectious diseasesincluding COVID-19, we are interested in understanding how COVID-19 vaccine designs differ in the type of immunity they trigger and the protection they produce.

New bivalent vaccines

Moderna and Pfizer-BioNTech, the two companies whose mRNA vaccines have been the primary options for COVID-19 vaccinations in all age groups, have new vaccine formulations on the way. An advisory committee of the Food and Drug Administration is scheduled to meet on June 28, 2022 to Evaluate the latest releases And to determine which one is most likely to be recommended for use in this fall’s booster shots.

Moderna’s new vaccine mixes bivalent mRNA that encodes the spike proteins of the original SARS-CoV-2 virus as well as the slightly different spike protein in the The most infectious omicron variant.

In early June 2022, Moderna said that in clinical trials, Its bivalent vaccine is superior to the original vaccine strainresulting in a stronger immune response and longer protection against the original SARS-CoV-2 and Its variants, including omicron.

Moderna later announced that its newest formula too Performs well against the latest omicron sub variants, BA.4 and BA.5which are quickly becoming the dominant strains in the United States due to the significantly stronger immune response stimulated by the new shot, Moderna expects to This protection may last up to a year and plans to Launching its new vaccine in August.

A new Moderna booster could be available by fall 2022.

and recently, On June 25, Pfizer-BioNTech also announced Results of two new COVID-19 vaccine formulations: a bivalent formulation consisting of mRNA that encodes the spike proteins of the original SARS-CoV-2 strain and the original variant BA.1 omicron, and a “monovalent” version directed only at the spike protein BA.1.

The company’s initial studies showed that both monovalent and bivalent vaccines stimulated antibodies that neutralized the newer omiconic sub-variants BA.4 and BA.5, although to a lesser degree than the BA.1 variant. However, the monovalent Pfizer vaccine Newer, better anti-virus antibodies against the omicron variant BA.1 than did the bivalent vaccine.

However, whether the differences in the levels of these antibodies seen with monovalent versus bivalent vaccines translate into different levels of protection against newer omicron variants remains to be determined in clinical trials.

Advances in Novavax Vaccine

Another vaccine formula working its way toward approval is Novavax, a vaccine created using the spike protein of the original SARS-CoV-2 virus. Novavax Vaccine Advantage of Presence Similar to traditional vaccinesLike the DTaP vaccines against diphtheria, tetanus and whooping cough, or vaccinations against other viral infections such as hepatitis and shingles. The Novavax vaccine has been clinically tested in South Africa, the United Kingdom and the United States and found to be Very safe and effective with efficacy 90% Against mild, moderate and severe forms of COVID-19.

Food and Drug Administration advisory committee Support Novavax Vaccine Early June 2022. Now, the FDA is reviewing changes Novavax made during the manufacturing process before making its decision to allow imaging.

In Australia, the Novavax vaccine has recently been provisionally registered as a booster for individuals 18 years of age and older. company Conducting a phase III clinical trial To determine if its vaccine can be used safely and effectively as a booster in people who have previously had mRNA vaccines.

When these new vaccines become available in the coming months, people will have much more options for mixing and matching vaccines in order to enhance the duration and quality of immune protection against COVID-19.

Novavax does not need to be frozen, so storing and delivering the vaccine is much easier.

Mix and match

Until then, clinical studies have shown that Mix and match Current vaccine types are an effective booster strategy. for example, Recent Studies We suggest that when adults who were fully vaccinated with any of the three original COVID-19 vaccines — Pfizer-BioNTech, Moderna, or Johnson & Johnson — received a booster dose with a different brand of vaccine than the one they received in their initial series, a similar or more robust immune response compared to the booster. The same brand of vaccine.

The vaccine has been mixed I found it safe and effective In different studies. The reason mixing vaccines may produce a more robust immune response is how each presents the elevated virus proteins to the immune system.

When SARS-CoV-2 mutates in regions of the spike protein, as was the case with both variants and sub variants, and attempts to evade immune cells, antibodies that recognize different parts of the spike protein can stop it in their tracks and prevent the virus from infecting the body’s cells. .

So whether you decide to get a booster shot now or wait until fall, it’s encouraging for many to know that more options are on the way.

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