Vaccine news dominated the COVID-19 headlines this week, as the ongoing vaccine roll-out hit a snag and leaders contemplated the potential for annual COVID-19 booster shots.

Vaccine Booster Shots

This week, the CEOs of two COVID-19 vaccine manufacturers and National Institute of Allergy and Infectious Diseases Director Dr. Anthony Fauci all acknowledged the likelihood that an annual COVID-19 vaccine — similar to the seasonal flu shot — will be needed. Both pharmaceutical manufacturers are studying the length of time over which their vaccines provide immunity, which will inform decisions about the need for a third dose and, if  deemed necessary, when it should be given after the first initial two doses are administered. Researchers of one of the mRNA-based vaccines are looking into how to combine the flu and COVID-19 vaccine so the public only need to get one annual shot rather than two.

Genomic Sequencing to Track Variants

Nearly 80,000 new infections were reported on Thursday, April 15, with the P.1 variant, originally found in Brazil, being the second most prevalent strain. With variants originating in the U.K., Brazil, and South Africa variants being detected in the U.S., there is an increasing need to track their transmission. Currently only 6% of COVID-19 cases are being sequenced. On, Friday April 16, the Biden administration committed to spending $1.7 billion of the last pandemic relief package to track coronavirus variants. Approximately $400 million will be dedicated to creating six new genomic epidemiology centers and $300 million for expanding the Centers for Disease Control and Prevention (CDC)’s bioinformatics fellowship program. The remaining $1 billion will be utilized for the coming years.

Vaccine Paused in U.S. Over Safety Concerns

After administering over 7.5 million doses, the only single-dose vaccine available in the U.S. was paused due to a linkage between the vaccine and rare and severe blood clots among six people. The type of blood clot — cerebral venous sinus thrombosis (CVST) — was only observed in women with thrombocytopenia (i.e., low levels of blood platelets). Despite the very low percentage of people affected by this (0.0001% among all vaccinated individuals), the federal government halted the vaccine under an abundance of caution to review these cases and access any significance. A CDC Advisory Committee on Immunization Practices met this week and is expected to reconvene next to week to make their recommendation on the vaccine.

Blood Clots Are Sometimes Observed After Vaccination and During COVID-19

As mentioned above, this week the U.S. paused the use of one of the three available vaccines in the U.S. due to six individuals developing severe blood clots after vaccination. Outside the U.S., reports have come out over the past several weeks of another vaccine — which uses a similar viral-vector vaccine technology — was also associated blood clots resulting in a brief pause in Europe but with Denmark halting distribution all together. For the two vaccines based on the newer mRNA vaccine technology development of blood clots was still found after vaccination but at slightly reduced odds (4 in 1 million vs. 5 in 1 million). 

However, regardless of the vaccine technology used, these odds are still better than the risk of developing blood clots from COVID-19 infection (39 in 1 million patients). Given that COVID-19 disease is known to cause severe blood clotting in some patients, it perhaps comes as no surprise that a vaccine based upon a protein found on the surface of the SARS-CoV2 virus particle could potentially contribute to the formation of clots in a very small segment of the population. Bearing in mind the rarity of these side effects and that over 860 million doses have been administered worldwide, these vaccines should still be considered safe and effective and important in our war against COVID-19 — in conjunction with mask wearing, social distancing and other mitigation measures.

Clinicians Are Warned About MIS-C

Over a thousand children with multi-system inflammatory syndrome (MIS) were examined in a recently published study which covered the period of March 2020 through January 2021. Most of these children had had a mild or asymptomatic COVID-19. The researchers explain that MIS in children (MIS-C) is a serious illness which is due to a delayed immune response to a SARS-CoV-2 infection. In this study, over 90% of children had more than four organ systems affected, and the symptoms peaked at two and five weeks after the initial infection. The article’s authors advised clinicians to remain watchful for MIS-C in pediatric patients presenting with inflammatory symptoms.