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Experts say monoclonal antibody treatment is not a substitute for COVID-19 vaccines


In the battle against COVID-19, patients diagnosed with the virus now have the option to receive a monoclonal antibody treatment, which has been shown to reduce COVID-19-related hospitalization or deaths in high-risk patients.

However, UC Davis Health infectious disease experts are warning patients that the monoclonal antibody treatment is not a replacement for the COVID-19 vaccine.

Stuart H. Cohen

“The monoclonal antibody therapy is a valuable tool for us when treating COVID-19, but in no way is it a substitute for vaccinations,” said Stuart Cohen, chief of the Division of Infectious Diseases and director of hospital epidemiology and infection control. “Early treatment with the monoclonal antibody therapy can reduce the risk of COVID-19 hospitalization or death, but it will not protect you against catching the virus and the vaccine does just that.”  

What are monoclonal antibodies?

Monoclonal antibodies are like the antibodies naturally made by the human body to fight viruses and are designed to target the coronavirus spike protein. When the antibodies bind to the spike protein, they block the virus from entering the body’s cells, which keeps the virus from making copies of itself and continuing to spread within the body.

“The monoclonal antibodies protect against severe illness by overwhelming the coronavirus infection while it is still mostly in the nose and throat," said Cohen. “However, the treatment remains limited because it needs to be given within a week after COVID symptoms begin. People may not always know when they were exposed or how long they have been infected.”

The monoclonal antibody therapy is a valuable tool for us when treating COVID-19, but in no way is it a substitute for vaccinations.Stuart Cohen, chief, Division of Infectious Diseases

Who can get monoclonal antibody treatment?

The FDA has authorized monoclonal antibody treatment for emergency use to treat high-risk patients who test positive and to prevent COVID-19 in a high-risk person who’s been exposed.

“At this time, we are treating immunocompromised patients with monoclonal antibodies who may still be vulnerable to COVID-19, even if they are fully vaccinated,” explained Cohen. “We are limited in the supply of this treatment, so it is appropriate to provide antibody drugs to those who are more susceptible to the virus.”

Currently the federal government is overseeing distribution of the treatment and the Department of Health and Human Services is deciding how many doses each state receives based on case rates and use of the treatment.

Monoclonal antibody treatment vs. vaccine

George Thompson

COVID-19 vaccines help stimulate and prepare a person's immune system to respond if they are exposed to the virus. However, monoclonal antibodies boost the immune system only after a person is already sick, speeding up their immune response to prevent COVID-19 from getting worse.

"One of the benefits of vaccines is that you develop the ability to create antibodies– you develop immunologic memory and can respond quickly if you have an infection," explained George Thompson, a UC Davis infectious diseases specialist. “Monoclonal antibody treatment can neutralize the virus, but it is only effective for a few months. A vaccine offers significant protection before being infected and for a much longer period.”

Thompson added that vaccinations offer protection to the overall community by preventing the virus from spreading and mutating to a more serious variant. The antibody treatment helps a single patient and does not keep people from catching the virus again later.

“The virus is going to continue to mutate and we are going to continue to see the emergence of different strains,” said Thompson. “The only way we are going to slow the rate of mutations of development of new strains is by large-scale vaccination.”

Learn how to schedule your COVID-19 vaccine appointment at UC Davis Health

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