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July 3, 2021

Delta Variants - What Level of Risk to Accept?

If you are not vaccinated, you are in danger of infection by the Covid-19 delta variant.  The virus searches out the vulnerable and right now we have to be concerned about those who will never get vaccinated - as we watch Covid cases increasing in many states in the US.  Most of the cases have been occurring in the unvaccinated, and the infected group now includes a larger percentage of unvaccinated children <12 years old and a lower percentage of the vaccinated elderly.  

It is possible to be vaccinated with two doses of the mRNA vaccines and still get Covid, although severe disease is uncommon.  Both the Pfizer and Moderna vaccines had vaccine efficacy rates of approximately 95%, and slightly less with the delta variant.  And J and J just reported strong persistent activity against the delta variant for a minimum of 8 months followup of their original trial subjects.  But that still leaves a small number of people who can still be infected after full vaccination.  The vaccine efficacy against the delta variant is a slightly lower than against the original virus strain (about 90% for the mRNA vaccines) allowing mostly asymptomatic and mild breakthrough cases to occur.  See Below


We each have to decide what level of risk keeps us comfortable.  For people who live in an area where cases are increasing, it makes sense to wear a mask indoors, even if you are fully vaccinated.  There is no good way to determine who is unvaccinated in some group encounters.  If you only had one dose of the mRNA vaccines, like 15 million Americans, the vaccine efficacy against the variants may be as low as 30-35% - and you should definitely protect yourself indoors and get your second dose.    I have been following the daily Covid cases in NY State, NYC, and Manhattan.  They now test almost 100,000 people per day as part of the Statewide Tracking Program and there are <0.5% positive cases in all 3 areas.  Genomic sequencing data of new cases is still being done in NYC on a subset of cases, and the delta (Indian) variant is increasing quickly as the alpha (UK) variant is decreasing.  Our family of 16 is all vaccinated except for 3 grandchildren less than age 12 - and my husband and I still avoid high risk indoor events. 


June 30, 2021

Longer Duration of mRNA Vaccine Efficacy?

The immune system is incredibly complex.  An antigen, foreign to the body, stimulates an immune response consisting of antibody production against the "invader," and activation of specific immune cells. Vaccine efficacy measures the full immune response and is measured by the number of people who get Covid 19 in the placebo group and those that get covid 19 in the vaccinated group.  B lymphocytes and plasma cells are responsible for antibody production and T helper and T killer cells are part of the cellular response to the infection, or in this case vaccine.  Antibody levels can be measured, but the titer slowly decreases over time.  However some committed B cells become memory B cells and remain in clusters in germinal centers of the lymph nodes.  Some memory plasma cells also remain after the foreign antigen is gone.

If that same foreign invader returns, these immune memory cells can be activated and stimulate another full immune response to the same virus or spike protein in the vaccine.  How long will it last last?  Sometimes for life (measles vaccine).  Investigators from Wash U. in St. Louis just published a scientific paper in Nature which demonstrates that there are both the memory B cells and memory plasma cells in active "germinal centers" in lymph nodes and they still appear active 15 weeks after vaccination.  Germinal centers in lymph nodes typically peak 1-2 weeks after vaccination and then wane.  The bottom line is exciting - we may have vaccine-induced immunity that will be more durable than was expected!  How long is unknown, but the investigators now have a way to monitor the immune response in addition to measuring antibody titers.  See Below


In the words of the scientists reporting this data, "the studies demonstrate that SARS-CoV-2 mRNA-based vaccination induces a persistent germinal center B cell response, enabling the generation of robust humoral immunity."  More variants could change all of this, but right now we can hope that booster shots will not be needed for the foreseeable future.


June 26, 2021

CDC and Myocarditis/Pericarditis with mRNA Vaccines

On June 12th I wrote a blog post about possible myocarditis/pericarditis as rare adverse effects of the mRNA Covid vaccines.

On Wednesday the CDC scientific vaccine advisory committee met to review the reported cases that have been adjudicated based on criteria for the diagnosis of myocarditis and pericarditis.  Scientists at the CDC presented all of the data that was accumulated since their last meeting, discussed the data, and then discussed the benefits vs risks for the continued use of the two mRNA vaccines against Covid 19. The final recommendation was that the benefit of the vaccines far outweigh the risks.

The side effects occur within 1 week after the administration of the 2nd vaccine dose and are usually chest pain and shortness of breath.  Symptoms and test results demonstrate that most cases are very mild and clear within several days with treatment like Motrin.  Most of the cases occur in males between the ages of 12 and 30, with an incidence of 12.6 cases per million second doses administered.   The majority of cases recover fully.   See Below for comparative data re: the incidence of myocarditis following Covid 19. 


A large study of Big Ten school college athletes demonstrated that 2.3% of athletes that recovered from Covid had heart abnormalities consistent with myocarditis.  CDC researchers estimated that every million 2nd doses of vaccine given to 12-17 year old boys might reduce myocarditis cases to 70, and prevent 5700 infections, 215 hospitalizations, and 2 deaths. These cardiac side effects of the vaccine are very, very rare and the consensus was that all adolescents and young adults should continue to get vaccinated.  The CDC will continue their extensive monitoring and follow these cases for 3 months.  Hopefully they will be able to better define the mechanism by which the vaccines cause the cardiac events.


June 23, 2021

Our Beach Visit is Over

We had a wonderful long family weekend with two of our children and their families.  It was so nice to be with some of our grandchildren that we only saw from a distance until we were vaccinated and some of them were too.  But our oldest grandchild had already started his camp counselor job and was missed.  My husband and I took AM beach walks, and on other days walked around this charming village.  In several weeks we will see our 3rd child, his wife, and 2 grandchildren in DC - and our last trip to visit them was early January 2020.  We are so happy to finally be able to travel a little. 

These are two more of the pen/ink drawings I did earlier in the pandemic when walking around our neighborhood.  Still not painted! I love drawing hats that change regularly in a local hat store.



 Favorite Dog Attire from our neighborhood "dog fashion store."


June 16, 2021

WOW! A 4th Covid Vaccine Later This Year

This week Novavax released the Phase 3 clinical trial data on their vaccine, although they probably won't seek an EUA from the FDA until next quarter.  They conducted their phase 3 trial in the US and Mexico.  Almost 30,000 volunteers (N=29,960) were randomized with 2 participants receiving Vaccine for every 1 receiving Placebo.  Vaccinations were given with 2 doses 3 weeks apart.  The vaccine is made with recombinant technology - the spike protein is made using the genetic sequence and then the spike protein is used as the antigen to stimulate an immune response.  There were 77 RT-PCR documented cases of Covid-19 in the volunteers (more than 7 days after the second dose), with 63 cases in the placebo group and 14 in the vaccinated group for an efficacy of 90.4%.  Ten cases were moderate and 4 severe in the placebo group.  There were no moderate or severe infections in the vaccinated group.  The vaccine was equally protective with high risk subjects, including participants 65+,  with comorbidities, or those with frequent covid exposures.  See below.



The method used to make the vaccine has been used for decades and includes influenza, hepatitis B, and HIV vaccines.  It only requires standard refrigeration making it easy to manufacture and administer the vaccine around the world.  The main adverse effects included local injection pain, headache, fatigue,  and myalgia.  There were also smaller, very successful Novavax studies in the UK and South Africa, and I will report on the main findings in those trials after I digest all of that separate data.