#kp.2

The vaccine that is best is the one that’s available to you and the one that you’re willing to get!

I’ve heard chatter about some people believing that Novavax provides better protection against COVID-19, and there just aren’t data to support that.

Novavax trials and real-world evidence collection lagged substantially behind the mRNA vaccines, so trying to compare measured vaccine effectiveness is comparing apples to oranges. Approximately 3.2 billion doses of mRNA vaccines have been administered compared to 2.6 million doses of Novavax vaccine.

All you need to know is that all of the COVID-19 vaccines demonstrated over 90% effectiveness in their initial clinical trials. All options protect against severe disease, hospitalization, and death. All of the available options have been reviewed by experts and deemed to be safe, comparably effective, and beneficial.

Novavax may have slightly lower reactogenicity compared to mRNA vaccines. Reactogenicity refers to symptoms that occur from the immune response: low grade fever, headache, lethargy, injection site soreness, lymphadenopathy (swollen lymph nodes), etc.

Will JN.1 vaccine formulation provide measurably different protection than the more closely matched KP.2 formulation that we will see in the mRNA vaccines? It is too hypothetical to know. That will be impacted by how much virus circulates within a community and how much more SARS-CoV-2 mutates as a result of genetic drift because of that spread.

(via Thread by @Daniel_E_Park on Thread Reader App – Thread Reader App)

Excellent broad cross neutralization to variants with the upcoming JN.1 Novavax COVID vaccine, including some of the best responses to variants that are likely to be dominant this late fall and early winter 

https://novavax.widen.net/s/zg79lxwknx/2024-q2-earnings-presentation

The latest CDC nowcast shows a rapid rise in KP3.1.1, which is the variant with best response to the NVX JN.1 vaccine. Others variants to keep an eye on include LB.1 (a direct JN.1 descendant) and LP.1 (KP1.1 descendant) https://covid.cdc.gov/covid-data-tracker/#variant-proportions

This follows an expected decline in KP.2 over the last few weeks, which is one reason why VRBPAC recommended not chasing this branch (KP.2 variant) but to target the trunk (JN.1).

Vaccines contain an active ingredient used to trigger generation of immune memory. That active ingredient, the antigen, is what initiates the immune response, starting with innate immune recognition and ending with adaptive immunity generation (read here for a more detailed summary on viral immunology).

Adaptive immune response leads to antibody by plasma cells, activation of helper T cells and cytotoxic T cells, and generation of memory B and T cells.

This process takes time, roughly 2 weeks after we encounter the foreign invader (either the vaccine antigen or an actual pathogen). Once memory B and T cells are created, the response to a second encounter is much quicker because all the preparation is already done. The adaptive immune system is ready to go: B cells can start spitting out antibodies, helper T cells can augment the B cell responses, and cytotoxic T cells can directly kill infected cells to limit the spread of infection.

Vaccines train the immune system in advance of an infection.

Myocarditis and pericarditis refer to inflammation of the heart muscle of the outer lining (pericardium). While these terms might sound scary and they have been used to instill fear about COVID-19 vaccines, they occur more often not related to vaccines.

The most common causes of myocarditis and pericarditis are viral infections.

Viral infections, including Coxsackievirus B, enteroviruses, echovirus, adenoviruses, parvovirus B19, Epstein-Barr virus, and - you guessed it - SARS-CoV-2 are the most common causes of myocarditis and pericarditis.

Infections with other pathogens, particularly bacterial species in Streptococcus and Staphylococcus genera as well as Mycobacterium tuberculosis are also major causes of myocarditis and pericarditis. Some parasitic and fungal infections can also be implicated, as well as autoimmune disorders, substance use, and physical trauma.

COVID-19 vaccines are much less likely to cause myocarditis and pericarditis than all of these. Rates of myocarditis and pericarditis after COVID-19 vaccination are orders of magnitude lower than rates after COVID-19 itself, even among the population that was noted to have rates higher than baseline: males 12-29 years old.

For some context, we are talking between 1 and 25 cases of myocarditis for every 100,000 vaccine doses administered to this demographic. That’s a proportion of 0.001% to 0.025% - so this adverse effect is not a common occurrence. I hope that assuages any concerns!

The Pfizer-BioNTech and Moderna COVID-19 vaccines use mRNA as the active ingredient. The mRNA is converted by our cells into the antigen, in this case, the spike protein of SARS-CoV-2.

The vaccine contains the mRNA, which is synthesized in the lab using a DNA template, the building blocks of RNA, and the enzyme that puts those building blocks together into the right order. mRNA is the molecule template for every protein in every organism. The mRNA sequence is a code for our cells to link amino acids together into functional proteins

mRNA is very fragile, so it is encased in a lipid nanoparticle (LNP) that protects it until it gets into our cells. When the vaccine is administered, the mRNA is released and is used to synthesize the spike protein which is displayed by cells that produced it. That spike protein is recognized by our innate immune cells like dendritic cells and macrophages as well as B cells, which initiates immune response and generation of memory immunity.

In contrast, Novavax is a protein-based vaccine, which contains the prefabricated antigen - the spike protein - instead of the template for it. To make the antigen, we turn cells into protein-producing factories in the lab.

Novavax uses Sf9 cells (moth cells) infected with an insect-specific virus that has been genetically engineered to contain the gene for the spike protein of SARS-CoV-2. These viruses will hijack the cellular machinery of the Sf9 cells to produce lots of spike proteins and baby viruses. Those will continue to reproduce and produce proteins, which will be harvested, purified, and formulated with the other ingredients in the final vaccine.

When the vaccine is injected, the antigen will be recognized by the same innate immune cells listed above, which will trigger the same immune response pathway.