TWO RSV VACCINES

Tieng Viet

Two RSV Vaccines

 

RSV vaccines were made available to the public earlier this year. I was quite elated by this medical advance and happily checked into the local pharmacy for a shot last October. All went fine except two weeks later I realized that in fact two vaccines existed. The local pharmacist made the choice for me without explanation, but did he make the right choice? Out of curiosity I looked up the information provided by the CDC¹ and FDA^2,3. Here’s what is at stake.

 

Arexvy (GSK) was approved by the FDA on May 3, 2023, followed by Abrysvo (Pfizer) on May 19, 2023. Both vaccines were approved for the prevention of lower respiratory tract disease (LRTD) caused by respiratory syncytial virus (RSV) in individuals 60 years of age and older.

 

Background information about RSV infection

RSV infection is a common respiratory illness caused by the respiratory syncytial virus. RSV can infect people of all ages, but it is most common in infants and young children. It can also seriously affect older adults and people with weakened immune systems. Young children, especially those under the age of 6 months are most impacted and will have at least one RSV infection by the time they are 2 years old. Infection is most common during the fall and winter months, but it can occur at any time of year. The most common symptoms of RSV infection are runny nose, cough, wheezing, fever, and difficulty breathing. In infants, RSV infection can also cause loss of appetite, lethargy, irritability, and apnea (brief pauses in breathing). The mortality rate from RSV infection varies depending on age and risk factors and is highest in infants under the age of 6 months and in older adults. It was estimated that the rate for infants under the age of 6 months is 0.5-1%, and 1-2% for older adults.

 

How to prevent RSV infection

There are several things we can do to help prevent RSV infection, including washing hands frequently, avoiding close contact with people who are sick, covering our mouth and nose when others cough or sneeze, and keeping children’s toys and surfaces clean. Children exhibiting any of the symptoms of RSV infection should be taken to a doctor right away. The availability of vaccines last May can only help.

 

Distinction between the two vaccines

Abrysvo(Pfizer) is generally recommended for older adults (age 60 and older) who are at high risk of RSV infection and complications. Abrysvo is also approved for use in pregnant women between 32 and 36 weeks of pregnancy. Arexvy (GSK) is also recommended for older adults (age 60 and older) who are at high risk of RSV infection and complications. However, Arexvy is not approved for use in pregnant women.

In short, there are two choices for older adults, but only one for pregnant women. The ideal patient profile for Abrysvo would include one or more of the following: an older adult (age 60 and older), a pregnant woman between 32 and 36 weeks of pregnancy, a person with weakened immune systems, or a person with chronic health conditions, such as asthma, chronic obstructive pulmonary disease (COPD), or heart disease. Only two factors make a patient more suitable for Arexvy: an older adult (age 60 and older) and a person with a history of allergic reactions to live attenuated vaccines. The latter points to the difference in manufacturing technology for the two vaccines.

 

Vaccine manufacturing technology

Arexvyis a subunit vaccine, which means that it contains only a small piece of the RSV virus, enough to trigger an immune response but not enough to cause infection. The RSV subunit is produced using recombinant DNA technology. This involves inserting the RSV gene into a harmless bacterium, which then produces the RSV protein. The RSV protein is then purified and combined with an adjuvant, which is a substance that helps to boost the immune response.

Abrysvois a live attenuated vaccine, which means that it contains a weakened form of the RSV virus. This weakened virus is not able to cause infection, but it can still trigger an immune response. The live attenuated RSV virus is produced using a process called cell culture. This involves growing the virus in human cells. Once the virus has grown, it is harvested and purified.

 

Comparison of Arexvy and Abrysvo Manufacturing Technology

Characteristic	Arexvy	Abrysvo
Vaccine type	Subunit	Live attenuated
RSV protein production method	Recombinant DNA technology	Cell culture
Adjuvant	Yes	No

 

Advantages and Disadvantages of Different Manufacturing Technologies

Subunit vaccines

Subunit vaccines are generally very safe, as they do not contain any live virus. They are also very effective at stimulating an immune response. In contrast subunit vaccines may require multiple doses to achieve full protection and may be less effective in people with weakened immune systems.

Live attenuated vaccines

Live attenuated vaccines are generally very effective at stimulating a strong and lasting immune response and may only require a single dose to achieve full protection. However, live attenuated vaccines can have side effects, like a mild infection with the virus, and therefore should be used with caution in people with weakened immune systems.

 

Summary of key differences between Arexvy and Abrysvo

Characteristic	Arexvy	Abrysvo
Vaccine type	Subunit	Live attenuated
RSV protein production method	Recombinant DNA technology	Cell culture
Adjuvant	Yes	No
Approved populations	Older adults (age 60 and older)	Older adults (age 60 and older), pregnant women between 32 and 36 weeks of pregnancy
Possible advantages for certain patients	Older adults, people who have a history of allergic reactions to live attenuated vaccines	People with weakened immune systems, people with chronic health conditions

 

It is important to note that both Arexvy and Abrysvo are safe and effective vaccines against RSV. The best vaccine for an individual will depend on their individual circumstances and risk factors. Patients should talk to their doctor and/or pharmacist to determine which vaccine is right for them.

 

Cost

Yes, there is a slight difference in cost between Arexvy and Abrysvo⁴. GSK estimated a single dose of Arexvy would cost $200 to $295, while Pfizer provided guidelines of $180-$270 for Abrysvo. However, it is important to note that these prices may vary depending on the pharmacy and your insurance coverage. Some pharmacies may offer discounts on Arexvy and Abrysvo, and your insurance may cover a portion or all the cost of the vaccine. It is important to contact your insurance company to find out what your coverage is for RSV vaccines. Please note that these prices are for the vaccine itself and do not include the cost of administration. The cost of administration may vary depending on the pharmacy or healthcare provider.

 

References

 

CDC source:

¹Respiratory Syncytial Virus (RSV) Immunizations

 

FDA sources:

²Arexvy

³Abrysvo

 

⁴Pricing