Vaccine playbook: what to expect and when

• Link to: Northwestern Now Story

CHICAGO — As the CDC begins to schedule the vaccine rollout, what can the public expect from a vaccination? Will we still have to be cautious about social contact and wear masks? How long before immunity kicks in? When will life return to normal?

Northwestern Medicine infectious disease and critical care experts offer a vaccine playbook below.

Dr. Michelle Prickett is an associate professor of medicine at Northwestern University Feinberg School of Medicine and a Northwestern Medicine pulmonary and critical care specialist. 

Dr. Robert Murphy is executive director of the Institute for Global Health at Northwestern University Feinberg School of Medicine and Northwestern Medicine infectious disease expert.

Dr. Benjamin Singer is assistant professor of medicine at Northwestern University Feinberg School of Medicine and a Northwestern Medicine pulmonary and critical care specialist.

For an interview, contact marla-paul@northwestern.edu. 

How long does it take for the COVID vaccines take effect? 

Dr. Benjamin Singer: “All but one of the COVID vaccines in phase 3 clinical trials require two injections a few weeks apart. Then it will take a few weeks to obtain the full protective effect. Vaccines generate an immune response that mimics someone getting infected with the virus itself. It takes weeks for a full protective response during which the body makes antibodies and long-lasting memory T cells that can rapidly respond if the vaccinated person encounters the virus to protect them.”

After vaccines become widely available, will we still have to be cautious? Wear masks? Social distance?

Singer: “I anticipate that masking and social distancing will be required for some time. Vaccines will take time to become widely available and take effect. Moreover, we may not see widespread vaccination of the population without concerted public health efforts on a national level. Note that adult vaccination rates for seasonal influenza rarely reach 50%.”

Dr. Michelle Prickett: “We will need some level of protection until everyone is able to be vaccinated and the case prevalence reaches levels able to be controlled with contact tracing.  Other factors, including how many people get vaccinated and how the virus is spreading in communities, will also affect our behaviors.” 

Dr. Robert Murphy: “When everyone who wants a vaccine has received a vaccine, and the proportion of people either vaccinated or who had covid-19 reaches a "herd immunity" threshold, we won't need masks or social distancing any longer.  Until we get to that point, we will have to follow the guidance of our public health officials and continue to wear masks and practice social distancing.”

How much will vaccine compliance affect our safety and return to normal life? 

Singer: “The vaccine appears to be very effective in preventing COVID-19. In addition, the few trial subjects who received the vaccine but still contracted COVID-19 had only mild illness.” 

Will we need to get a new COVID-19 vaccine every year like the flu vaccine? If so, why? 

Singer: “Recommendations for repeat vaccination will depend on the observed duration of protection as participants from vaccine clinical trials are followed over time.”

Murphy: “We are not expecting to have a different vaccine annually with SARS-CoV-2.  If the virus were to mutate and become resistant to one or more of the vaccines, then we would have to change to a different vaccine with a different target.” 

When might a normal life as we knew it resume?  

Prickett: “If vaccines are widely available by the spring, and there is a distribution plan, I would imagine we could expect the restrictions to ease and return to normal by mid to late summer.” 

Murphy: “In the latter half of 2021, things will be very different and much better than now, however a pre-covid state is more likely in 2022.”  

When will the “average” person, not high risk, be able to take the vaccine?

Murphy: “As production ramps up and distribution networks are developed, the vaccines will become available to anyone who wants to take them. That should occur sometime mid-year 2021. Still, it will take many months to vaccinate those that want it as logistically, it will be challenging.”

Does a person who has been infected with COVID-19 still need to get the vaccine?

Prickett: “Patients who have been infected with COVID-19 should still get the vaccine.  We are not certain that a prior infection will lead to lifelong immunity. Current data suggests a prior infection could confer immunity for around six months.”