Vaccines and you: what the Caltech virologists found out
That’s the perspective from one member of Pamela Bjorkman’s laboratory at Caltech, where we study immune responses to pathogenic viruses, with the goal of designing new therapeutics and vaccines. We’d like to share our thoughts about the current COVID-19 situation. With the development of several highly effective vaccines, science has something to offer as protection against COVID-19 disease, and we want to provide accurate information about vaccines to help you protect yourself and your loved ones.
We study how our immune system can protect us against viruses such as human immunodeficiency virus (HIV), Zika and SARS-COV-2, the virus that causes COVID-19. When we are infected with a virus, our immune system makes proteins called antibodies to fight the virus. Antibodies do this by recognizing features on the virus surface and then either preventing it from infecting cells or marking it for elimination. However, some antibodies work better at controlling a virus than others. By studying where the best antibodies stick to the virus, scientists learn how to make vaccines that help our immune system make optimal antibodies, which are then ready to protect us from severe symptoms, hospitalization, or death if we become infected. Vaccines rarely block viral infection itself (e.g., the polio vaccine prevents paralysis and other complications from poliovirus infection, not infection itself). A vaccine is like having a fire extinguisher in your kitchen — it won’t prevent a fire from starting, but you can put it out more quickly if you have the extinguisher on hand.
Making vaccines can be difficult for viruses such as HIV and Zika. The vaccines for COVID-19
In this Sept. 24, 2020, photo an employee of SinoVac works in a lab at a factory producing its SARSCoV-2 vaccine for COVID-19 in Beijing.
are extremely effective at delivering instructions to our bodies to make strong antibodies; thus, most people who get a COVID-19 vaccine have mild or no symptoms if they later become infected. On the other hand, the majority of people who are hospitalized from severe illness have not received a vaccine.
So how do vaccines instruct our immune system make antibodies? Vaccines provide the body with a piece of a virus where antibodies bind, which helps your immune system recognize that virus if you later become exposed. All approved COVID-19 vaccines available in the United States provide the immune system with genetic material (DNA or mRNA) to make a piece of the SARSCoV-2 virus called the “spike.” Once cells that received the vaccine make spike, a viral fusion protein, they destroy the DNA or mRNA delivered by the vaccine (which means that COVID-19 vaccines are not a form of gene therapy). Then, the cells display spike on their surface, and because it isn’t recognized as one of our proteins, the immune system gets to work: it will make antibodies and other immune responses that recognize spike, and these will be ready if you are ever exposed to SARS-CoV-2.
You may have heard that COVID-19 vaccinations can cause infertility. However, multiple studies have found no effects on fertility of COVID-19 vaccines. This bit of misinformation likely arose from the idea that immune responses to the SARS-CoV-2 spike could harm a human placental protein involved
in fusion of cells. As it happens, the only similarity between coronavirus spike and the placental fusion protein is that they both function in fusion. But they do not look like each other (we say this as structural biologists), and they do not have similar sequences. Structural and/or sequence similarity would be required for cross-reactive immune responses from the COVID-19 vaccine to damage the placental protein.
Many have raised the concern that the current vaccines were developed so quickly, worrying that they may not have been properly evaluated for safety. However, both DNA and mRNA COVID-19 vaccines have been proven safe and effective using the same processes and standards that other vaccines required. Short, and inter-related, answers for how it was possible to develop vaccines so quickly are “money” and “emergency.”
Because COVID-19 was (and still is) a world-wide emergency, there was enough funding to conduct the phases of clinical trials concurrently — so instead of doing a Phase 1 trial with a <100 participants, evaluating those results and only then raising money for Phase 2 and Phase 3 trials with more participants, it was possible to use funding and emergency authorizations to perform all stages of the trials more efficiently without compromising safety. Also, the high infection rates when clinical trials were running provided researchers with efficacy data quickly. In addition, although the first mRNA vaccines were approved
only last year, the technology has been in the works for over 30 years, including human clinical trials prior to COVID-19 that revealed no safety concerns. mRNA-based vaccine technology is easier than traditional vaccine technologies that involve inactivated viruses or protein subunits from viruses. The incredible success of the mRNA vaccines — providing up to 95% protection after two doses — is almost unparalleled. The most important component, however, of any of the vaccines ... is you.
The human component of vaccination is crucial, but also messy and complicated. It’s easy for us as scientists and medical professionals to say that we need vaccines in arms today, but this ignores the very real reasons why people may delay or refuse vaccination. You may encounter conflicting information and be unsure of what to trust. You may want to be vaccinated, but are unable to take time off work to do so. You may even be part of a community that has been marginalized or hurt by the medical establishment. We encourage you to reach out to community leaders, friends, neighbors or physicians to find support and talk through your concerns. And what can you do as a vaccinated person? If you’re in a position to help drive someone to an appointment, babysit, or cook a meal, now is the time. Most importantly, however: listen.