A recent study by Johns Hopkins Medicine researchers provides evidence that CD4+ T lymphocytes — immune system cells also known as helper T cells — produced by people who received either of the two available messenger RNA (mRNA) vaccines for COVID-19 persist six months after vaccination at only slightly reduced levels from two weeks after vaccination and are at significantly higher levels than for those who are unvaccinated.

The researchers also found that the T cells they studied recognize and help protect against the delta variant of SARS-CoV-2, the virus that causes COVID-19. According to the U.S. Centers for Disease Control and Prevention, the delta variant — currently the predominant strain of SARS-CoV-2 in the United States — causes more infections and spreads faster than earlier forms of the virus.

The study findings were first reported online Oct. 25, 2021, in the journal Clinical Infectious Diseases.

“Previous research has suggested that humoral immune response — where the immune system circulates virus-neutralizing antibodies — can drop off at six months after vaccination, whereas our study indicates that cellular immunity — where the immune system directly attacks infected cells — remains strong,” says study senior author Joel Blankson, M.D., Ph.D., professor of medicine at the Johns Hopkins University School of Medicine. “The persistence of these vaccine-elicited T cells, along with the fact that they’re active against the delta variant, has important implications for guiding COVID vaccine development and determining the need for COVID boosters in the future.”

To reach these findings, Blankson and his colleagues obtained blood from 15 study participants (10 men and five women) at three times: prior to vaccination, between seven and14 days after their second Pfizer/BioNTech or Moderna vaccine dose, and six months after vaccination. The median age of the participants was 41 and none had evidence of prior SARS-CoV-2 infection.

CD4+ T lymphocytes get their nickname of helper T cells because they assist another type of immune system cell, the B lymphocyte (B cell), to respond to surface proteins — antigens — on viruses such as SARS-CoV-2. Activated by the CD4+ T cells, immature B cells become either plasma cells that produce antibodies to mark infected cells for disposal from the body or memory cells that “remember” the antigen’s biochemical structure for a faster response to future infections. Therefore, a CD4+ T cell response can serve as a measure of how well the immune system responds to a vaccine and yields humoral immunity.

In their study, Blankson and colleagues found that the number of helper T cells recognizing SARS-CoV-2 spike proteins was extremely low prior to vaccination — with a median of 2.7 spot-forming units (SFUs, the level of which is a measure of T cell frequency) per million peripheral blood mononuclear cells (PBMCs, identified as any blood cell with a round nucleus, including lymphocytes). Between 7 and 14 days after vaccination, the T cell frequency rose to a median of 237 SFUs per million PBMCs. At six months after vaccination, the level dropped slightly to a median of 122 SFUs per million PBMCs — a T cell frequency still significantly higher than before vaccination.

The researchers also looked six months after vaccination at the ability of CD4+ T cells to recognize spike proteins atop the SARS-CoV-2 delta variant. They discovered the number of T cells recognizing the delta variant spike protein was not significantly different from that of T cells attuned to the original virus strain’s protein.

Although the study was limited because of the small number of participants, Blankson feels it pinpoints areas that merit further research.

“The robust expansion of T cells in response to stimulation with spike proteins is certainly indicated, supporting the need for more study to show booster shots do successfully increase the frequency of SARS-CoV-2-specific T cells circulating in the blood,” says Blankson. “The added bonus is finding that this response also is likely strong for the delta variant.”

Along with Blankson, the members of the study team from Johns Hopkins Medicine are study lead author Bezawit Woldemeskel and Caroline Garliss.

This study was supported by the Johns Hopkins COVID-19 Vaccine-related Research Fund.

The authors do not have financial or conflict of interest disclosures. 

Although extreme poverty in the United States is low by global standards, the U.S. has the worst index of health and social problems as a function of income inequality. In a newly published article, Bettina Beech, clinical professor of population health in the Department of Health Systems and Population Health Sciences at the University of Houston College of Medicine and chief population health officer at UH, examines poverty and racism as factors influencing health.

“A common narrative for the relatively high prevalence of poverty among marginalized minority communities is predicated on racist notions of racial inferiority and frequent denial of the structural forms of racism and classism that have contributed to public health crises in the United States and across the globe,” Beech reports in Frontiers in Public Health. “Racism contributes to and perpetuates the economic and financial inequality that diminishes prospects for population health improvement among marginalized racial and ethnic groups. The U.S. has one of the highest rates of poverty in the developed world, but despite its collective wealth, the burden falls disproportionately on communities of color.” The goal of population health is to achieve health equity, so that every person can reach their full potential.

Though overall wealth has risen in recent years, growth in economic and financial resources has not been equally distributed. Black families in the U.S. have about one-twentieth the wealth of their white peers on average. For every dollar of wealth in white families, the corresponding wealth in Black households is five cents.

“Wealth inequality is not a function of work ethic or work hour difference between groups. Rather, the widening gap between the affluent and the poor can be linked to unjust policies and practices that favor the wealthy,” said Beech. “The impact of this form of inequality on health has come into sharp focus during the COVID-19 pandemic as the economically disadvantaged were more likely to get infected with SARS CoV-2 and die.”

A Very Old Problem 

In the mid-1800’s, Dr. James McCune Smith wrote one of the earliest descriptions of racism as the cause of health inequities and ultimately health disparities in America. He explained the health of a person “was not primarily a consequence of their innate constitution, but instead reflected their intrinsic membership in groups created by a race structured society.”

Over 100 years later, the Heckler Report, the first government-sanctioned assessment of racial health disparities, was published. It noted mortality inequity was linked to six leading causes of preventable excess deaths for the Black compared to the white population (cancer, cardiovascular disease, diabetes, infant mortality, chemical dependency and homicide/unintentional injury).

It and other reports led to a more robust focus on population health over the last few decades that has included a renewed interest in the impact of racism and social factors, such as poverty, on clinical outcomes.

The Myth of Meritocracy

Beech contends that structural racism harms marginalized populations at the expense of affording greater resources, opportunities and other privileges to the dominant white society.

“Public discourse has been largely shaped by a narrative of meritocracy which is laced with ideals of opportunity without any consideration of the realities of racism and race-based inequities in structures and systems that have locked individuals, families and communities into poverty-stricken lives for generations,” she said. “Coupled with a lack of a national health program this condemns oppressed populations such as Black and Hispanic Americans, American Indians, and disproportionately non-English speaking immigrants and refugees to remain in poverty and suffer from suboptimal health.”

Keys to Improvement

The World Health Organization identified three keys to improving health at a global level that each reinforces the impact of socioeconomic factors: (1) improve the conditions of daily life; (2) tackle the inequitable distribution of power, money and resources; and (3) develop a workforce trained in and public awareness of the social determinants of health.

The report’s findings highlight the need to implement health policies to increase access to care for lower-income individuals and highlight the need to ensure such policies and associated programs are reaching those in need.

“Health care providers can directly address many of the factors crucial for closing the health disparities gap by recognizing and trying to mitigate the race-based implicit biases many physicians carry, as well as leveraging their privilege to address the elements of institutionalized racism entrenched within the fabric of our society, starting with social injustice and human indifference,” said Beech.

As we give thanks at the holidays, it’s easy to overlook someone important: your past self.

While it’s well documented that gratitude toward others can improve wellbeing, two University of Florida scientists find that gratitude toward your past self also has benefits.

Does thanking yourself seem a bit…selfish? The researchers, UF psychology professor Matt Baldwin, Ph.D., and undergraduate student Samantha Zaw, think not.

“Despite the fact that past gratitude is self-focused, it reminds people that they’re part of a bigger story and that they have the power to grow,” Baldwin said. “It’s possible this promotes a pay-it-forward type of mentality.”

Gratitude is what psychologists call a self-transcendent emotion, one that lifts us out of the everyday and expands our perspective, which can help us get along with each other better. In a recent experiment, Baldwin and Zaw asked participants to write brief gratitude letters. The first group thanked someone else, the second thanked themselves, while a third, the control condition, wrote about a positive experience they’d had. Zaw and Baldwin then surveyed the participants about their self-perception after writing the letter. Although the results are not yet published, early analysis shows that the exercise gave the other- and self-focused gratitude groups a sense of redemption and helped them feel they were morally good people. However, the group that wrote to themselves scored higher on both measures.

The past-self group also saw a benefit the others didn’t: an increase in the self-awareness measures of clarity, authenticity and connectedness.

“Unlike gratitude toward others, being appreciative of ourselves carries an added benefit of truly understanding who we are and feeling connected to ourselves,” said Zaw, a McNair Scholar who has been working with Baldwin since her freshman year as part of UF’s Emerging Scholars Program.

Zaw and Baldwin’s research — the first known data gathered on past-self gratitude — was inspired by a Reese’s cup. When Baldwin’s co-worker, boredom researcher Erin Westgate, returned to the office after pandemic lockdown, she was delighted to discover a peanut butter cup she had squirreled away in her desk.

“She texted me like, ‘Oh my gosh, my past self left my future self a Reese’s,’” Baldwin recalled. “I was like, ‘Wait a second. You’re expressing gratitude towards something your past self had done. We have to study this.’”

As Zaw and Baldwin dug into previous studies, they found plenty on gratitude toward others and a few on self-compassion, but nothing on past-self gratitude. They designed the letter-writing experiment to test its effects, presenting their findings at the Society of Southeastern Social Psychologists in October and at the upcoming meeting of the Society for Personality and Social Psychology in February.

If you’re curious about the benefits of self-gratitude, Zaw offered a way to try the experiment at home, maybe as a new Thanksgiving tradition. Take a few minutes to write a thank you message to someone else, and another to yourself for something you did in the past. Sharing what you wrote could foster connections between loved ones, she said, but the exercise can also pay dividends if you try it on your own.

“At Thanksgiving and Christmas, we focus on other people, but self-care is really needed too, especially if we want to feel more clear about ourselves,” she said. “Maybe it can even lead to a better vision for ourselves for the next year.”