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Vaccines: Herd Immunity, Passports, Reaching the Underserved

Three Duke experts examine pressing vaccination issues

Part of the The Briefing: The Impact of COVID-19 Series
Vaccines: Herd Immunity, Passports, Reaching the Underserved

DURHAM, N.C. -- As the COVID-19 vaccinations roll out with increasing speed, questions are now arising about herd immunity, the need to reach underserved populations, and a proposed passport program that would provide proof of a person鈥檚 vaccination record.

Three Duke scholars tackled these and other issues Wednesday in a virtual briefing for journalists.

Watch the briefing on .

Here are excerpts:

ON HOW MANY AMERICANS NEED VACCINE

Dr. Emmanuel Walter Jr., chief medical officer, Duke Vaccine Institute

鈥淭he best estimates from all the experts we can see is approximately 70 to 85 percent of the population needs to receive a vaccine to achieve what we call herd protection. I like to actually call it community protection. That鈥檚 a pretty high bar to achieve. There are other infectious diseases, for example, measles, where we actually have to achieve closer to 95 percent coverage in the population, and we do pretty well with that.鈥

鈥淲e really have made some substantial and incredible progress over the past several months. We have 167 million doses of vaccine administered and about 107 million people have received a first dose. So how does that translate? About 33 percent of the population has received a first dose of vaccine and about 19 percent of the population now is fully vaccinated. That鈥檚 still a pretty big gap when you鈥檙e looking to try to achieve 75 percent in the population.鈥

鈥淲e鈥檙e making some really nice progress. We still have some room to go. The one particular population where we really achieved good coverage is those who are at highest risk in the oldest age group. If you look at people who are over 65 percent, 75 percent have received one dose of vaccine and 55 percent are fully vaccinated. That鈥檚 really good news.鈥

鈥淭he one group that I think we really need to add into the equation to achieve community protection 鈥 are children. I think, as you all know, clinical trials for children are well underway. Children make up about 23 percent of the population. So if you automatically discount vaccinating children you鈥檙e already down to about 75 percent or so of the population that鈥檚 getting vaccinated if you don鈥檛 vaccinate children. So reaching our goal to achieve herd immunity, I think we need to consider vaccinating children.鈥

ON ADDRESSING VACCINE HESITANCY

Lavanya Vasudevan, family medicine and community health professor

鈥淐ompared to December when the vaccines were first approved, we have doubled the proportion of U.S. adults willing to be vaccinated. The majority of the shift in willingness to be vaccinated is driven by the high efficacy of the vaccines and their safety profiles. Many people who initially wanted to wait and see how the vaccines turned out are now willing to be vaccinated.鈥

鈥淪till, one of the biggest hurdles is with vaccine access and making sure everyone who wants to get vaccinated is able to do so. Although about 60 to 65 percent of U.S. adults want the vaccine, only half have received one dose of the vaccine so far.鈥

鈥淲e know challenges with vaccine access and appointment scheduling can create frustration and reduce trust in the vaccination program. We need to make sure we have the ability to provide vaccines to everybody who is eligible.鈥

ON PROS, CONS OF VACCINE PASSPORTS

Nita Farahany, professor of law, philosophy

鈥淧eople are anxious to get back to some sense of post-pandemic normal. Going to a restaurant. Getting on an airplane. Or even gathering with people in groups in places indoors where we haven鈥檛 been able to do so 鈥 people think a vaccine passport 鈥 would give them a greater sense of security.鈥

鈥淭hat could be a big boost to the economy. It could give people a sense of safety and an ability to re-engage.鈥

鈥淭here are a lot of risks, though, to adopting this kind of vaccine passport approach.鈥

鈥淭he moment at which it might be ethical to adopt it is the moment when we might not need them anymore.鈥

鈥淲e鈥檙e starting to develop data that shows people who are vaccinated are unlikely 鈥 to get infected themselves, therefore unlikely to spread it to other people. But there鈥檚 still a risk. If people get the sense there鈥檚 no risk of infection, they may unwittingly start to let down their guard in ways that are particularly dangerous.鈥

鈥(There is) an equity concern. You鈥檝e heard already about the distribution of the vaccines. We鈥檙e getting there. We鈥檙e doing a great job of starting to roll it out. But notice the way we prioritize vaccination wasn鈥檛 by the people who were economically hit the hardest by the pandemic. Instead it was the people most vulnerable to serious disease or death.鈥

鈥淚f we had been able to contain the virus more, we might have had a different strategy where you would distribute it to people most likely to be out and about spreading it to other people in society. Or you might have chosen to distribute it to the people who were most economically harmed and therefore need to be able to re-integrate into society more quickly.鈥

鈥淚f we condition participation in society based on access to a vaccine passport, and we do so now, at this moment, when at least half the U.S. population don鈥檛 have access to the vaccine 鈥 then what you鈥檒l see is a widening gap. Jobs lost to the pandemic will go to people who were able to gain earlier access to the vaccines.鈥

鈥淭he minority populations of the United States have been hardest hit. Many of them didn鈥檛 have the benefit of being able to work from home or work remotely. A lot of them were essential frontline workers 鈥 or individuals who lost jobs because jobs started to shut down.鈥

鈥淭hose individuals, if we start to say you can鈥檛 participate in society or in these different activities, we expect to see a widening gap 鈥 and a greater loss of public trust in minority populations who are already experiencing a significant amount of distrust with respect to social institutions and also public health institutions. We need to be able to continue to cultivate trust in individuals such that they鈥檒l want to get vaccinated.鈥

鈥淭hese are drugs that do not have full regulatory approval. That鈥檚 not a small point. These are drugs that have an emergency use authorization. So far, it seems like they have robust efficacy and it seems like they have robust safety. But we don鈥檛 know for sure yet.鈥

鈥淯p until we have full regulatory approval for a drug, requiring people to take it 鈥 and that鈥檚 what a vaccine passport would do 鈥 it conditions participation on taking a drug that hasn鈥檛 received full regulatory approval. That essentially conscripts people to being research participants, which isn鈥檛 how we run clinical trials. It isn鈥檛 how we address the issue of informed consent in society.鈥

鈥淚 think it would erode public trust in the regulatory process.鈥

ON NEED FOR GLOBAL VACCINATIONS

Lavanya Vasudevan

鈥淯nless we can achieve widespread vaccinations and achieve herd immunity on a global scale, we are not going to be safe in the U.S. I think access is a big issue. According to UNICEF, over 130 countries have no access to the COVID-19 vaccine.鈥

鈥淭here are a lot of logistical and access-related challenges that play a role.鈥

Dr. Emmanuel Walter

鈥淚 do think access is going to be a big issue, probably more than hesitancy. There always will be vaccine-hesitant people but I worry about the access issue. One of our big drivers here in the United States 鈥 is the emergence of viral variants. If we don鈥檛 get a handle on that globally we may see the emergence of more variants and some of them could be more resistant to coverage by our current vaccines.鈥

鈥淚 think we do need to really make an effort to attack this on a global scale.鈥

ON OPPOSITION TO VACCINE PASSPORTS

Nita Farahany

鈥淚鈥檝e been surprised that there have been uncomfortable bedfellows together in opposition to vaccine passports. On the one hand, you have a lot of people talking about the equity issue that arise from the use of vaccine passports. And that鈥檚 an issue that鈥檚 a moment in time. If you鈥檙e talking about the U.S. 鈥 at some point there will be widespread availability of the vaccines such that anybody that wants to have the vaccine can have it, and they鈥檒l have full regulatory approval. At that moment in time, some of the equity issues will no longer exist.鈥

鈥淚n some places there are strong libertarian and conservative voices joining and arguing there鈥檚 a liberty interest in not being required to have vaccinations. We have in the past and in certain contexts, whether it鈥檚 in health care settings or in education 鈥 required vaccinations, and it鈥檚 permissible. The mechanism by which this type of vaccine passport is rolling out is very different. We need to have a moment where we actually reflect on that and decide what the best pathway forward is.鈥

鈥淪uddenly you have a lot of corporations trying to get into the game of owning different biometric information about individuals that would serve as a gateway to access and entry to different settings.鈥

鈥淭here is a political strain starting to emerge around a liberty interest; there鈥檚 this other strain really around equity and public trust. They all share in common an opposition. My hope is it won鈥檛 become a conservative versus liberal; instead people see there鈥檚 lot of commonality to the concerns. We need to look at the risks 鈥 and figure out what the right approach is.鈥

ON CHILDREN, SCHOOL AND VARIANTS

Dr. Emmanuel Walter

鈥淢ost of the information we have to date in terms of school attendance suggests it is OK for children to attend school if certain precautions are in place with social distancing and masking. I think in communities where that鈥檚 been done, it鈥檚 been done fairly successfully to date.鈥

鈥淚 do think the UK variant is a little bit different. We don鈥檛 have as much experience here in this country with that at this point. I don鈥檛 know we know for sure that should change, at this point, our recommendations for school attendance.鈥

鈥淚t鈥檚 really important for children鈥檚 wellbeing to attend school 鈥 for children and for parents. I don鈥檛 think we need to rush to change things without more information at this point.鈥

ON VACCINE PASSPORTS VS CURRENT TRAVEL REQUIREMENTS

Nita Farahany

鈥淭he drugs included on those lists required for international travel have widespread availability for anybody who needs them; have full regulatory approval; are used in very limited context; are not governed by third-party corporations.鈥

鈥淚 worry that the use in a much broader context to participate in any aspect of society creates all of the other concerns 鈥 equity, distribution concerns, issues that we don鈥檛 have full regulatory approval, privacy concerns, etc.鈥

鈥淚t鈥檚 not that we cannot require vaccination in certain context; we do and we can. It鈥檚 a question of whether or not these passports are appropriate to be used by society across the board.鈥

ON SUCCESSFUL VACCINE MESSAGING

Lavanya Vasudevan

鈥淭he messaging strategies that have been successful have been very tailored to (underserved) communities. Really, the use of tailored strategies is what鈥檚 been important.鈥

鈥淎ccess is still a major issue for those communities. It鈥檚 very important to bring vaccines to those communities. Make sure they have access. Many are health care deserts, don鈥檛 even have pharmacies in some cases. So we really need to think about how to bring vaccines there.鈥

ON WHETHER A VACCINE PASSPORT WOULD BE 鈥榁OLUNTARY鈥

Nita Farahany

鈥淭hey鈥檙e all relatively introduced in a voluntary sense. You don鈥檛 have to go to a restaurant. You don鈥檛 have to work. You don鈥檛 have to go to school. That鈥檚 sort of how people frame the voluntary-ness argument. But it鈥檚 not really voluntary. If people who accept the passport condition your participation on you having the passport 鈥 it is not voluntary in the sense of what we think of as a truly free and autonomous choice.鈥

ON PEOPLE WHO CANNOT GET VACCINE FOR MEDICAL REASONS

Dr. Emmanuel Walter

鈥淭here鈥檚 really very few absolute contra-indications to getting a vaccine. You have to be of the right age for which it鈥檚 indicated. The only medical contra-indication is if there鈥檚 an allergy to the vaccine. Unlike some other vaccines, for example live virus examples, these vaccines really are pretty available for use in most of the population.鈥

ON FLU SEASON AND COMPLACENCY

Lavanya Vasudevan

鈥淚t鈥檚 something we need to keep in mind. The fact that there has to be a new vaccine developed each year 鈥 and the efficacy of the vaccine may vary. That by itself is a big reason why people choose not to get the vaccine. And there are all these myths about how you get the flu from the flu vaccine. We are hearing similar stories about COVID-19.鈥

鈥淚 think it鈥檚 not something we should take for granted now that we are reopening businesses and schools. We aren鈥檛 as isolated as we were last fall. There鈥檚 a really good chance the flu makes a comeback.鈥

Faculty Participants

Nita Farahany
 is a professor of law and a professor of philosophy at Duke and founding director of . Farahany studies the ethical, legal and social implications of emerging technologies.
 

Lavanya Vasudevan
 is an assistant professor in the Department of Family Medicine and Community Health and the Global Health Institute at Duke. She is also a faculty affiliate at Duke鈥檚 Center for Health Policy and Inequalities Research.

Dr. Emmanuel Walter Jr.
 is chief medical officer of the Duke Human Vaccine Institute, where he directs the Duke Vaccine and Trials Unit. Walter is also a professor of pediatrics at 老牛影视 School of Medicine. 

Duke experts on a variety of other topics related the coronavirus pandemic can be found