The coronavirus disease 2019 (COVID-19) pandemic substantially disrupted well-child visits and vaccinations in the United States.1,2 Parent hesitancy for pediatric COVID-19 vaccines3 and widespread vaccine misinformation during the pandemic may have affected parent confidence in routine childhood vaccines. Little is known beyond 2 studies: 1 involved a convenience sample from a single medical center4 ; the other only evaluated adolescent vaccines.5 Using longitudinal data from a nationally representative sample, we assessed how parents’ confidence in childhood vaccines changed during the pandemic.
Methods
We analyzed data from the Understanding America Study (UAS), a probability-based Internet panel of ∼9500 United States adults.6 Panel members were recruited by using address-based sampling and provided with Internet-enabled tablets if needed.
Understanding Coronavirus in America surveys were administered to the UAS panel (in English and Spanish) biweekly from April 1, 2020 to February 16, 2021, then monthly through July 20, 2021, with 2 additional surveys from September 23 to October 1, 2021 and February 1 to March 30, 2022 (Supplemental Information). In every wave except for 2, respondents were asked whether they agreed with 4 statements (presented in random order) about childhood vaccines: “Childhood vaccines, such as those for measles or chicken pox: 1) provide important benefits to society; 2) may lead to illness or death; 3) have many known harmful side effects; 4) are useful and effective” (Response options: Strongly Agree/Agree/Disagree/Strongly Disagree). These questions were omitted in the June 10 to July 8, 2020 and July 8 to August 5, 2020 surveys because of cost constraints.
We identified parents of children aged 0 to 17 years among UAS panel members on the basis of responses to My Household surveys, administered quarterly to all panel members to assess household characteristics (Supplemental Information). We examined trends in the percentage of parents who strongly agreed or agreed with each statement. For the “illness or death” and “harmful side effects” statements, we used linear regression models with cluster robust standard errors at the respondent level to assess characteristics associated with a change between the first (April 1–April 28, 2020) and most recent (Feb 1, 2022–March 30, 2022) waves. Analyses used SAS 9.4 (Cary, NC), were adjusted by using survey sampling weights, and used exempt data under the UAS Data Use Agreement.
Results
Across all survey waves, the weighted sample size of parent respondents ranged from 1412 to 1987. Parent response rates ranged from 96.9% to 71.5% in the first and last survey waves, respectively, and were similar to those of the overall panel (97.1% and 75.8% for the first and last waves, respectively).
From April 2020 to March 2022, the percentage of parents who agreed with the “important benefits” and “useful and effective” statements remained stable and high, ranging from 89.5 to 92.5% and from 89.3 to 93.2%, respectively (Fig 1). By contrast, the percentage of parents who agreed with the illness or death and harmful side effects statements increased significantly by 13.2% (95% confidence interval [CI]: 9.4% to 16.9%) and 6.1% (95% CI: 2.2% to 9.9%), respectively (Tables 1 and 2). Statistically significant increases were observed for most parent subgroups (with overlapping CIs noted, suggesting no statistically significant differences between subgroups).
Percentage of parents who strongly agree or agree that childhood vaccines provide important benefits to society, are useful and effective, may lead to illness or death, have many known harmful side effects; April 1, 2020 to March 30, 2022. Error bars correspond to the 95% CI for each point estimate.
Percentage of parents who strongly agree or agree that childhood vaccines provide important benefits to society, are useful and effective, may lead to illness or death, have many known harmful side effects; April 1, 2020 to March 30, 2022. Error bars correspond to the 95% CI for each point estimate.
Percentage of Parents Who Stated in April 2020 and February 2022 That They Strongly Agree or Agree That Childhood Vaccines May Lead to Illness or Death, Including Change Over Time
| Childhood Vaccines May Lead to Illness or Death | ||||||
|---|---|---|---|---|---|---|
| April 1–April 28, 2020 | Feb 1–Mar 30, 2022 | |||||
| Weighted Sample Size | Strongly Agree or Agree, % (95% CI) | Weighted Sample Size | Strongly Agree or Agree, % (95% CI) | Change Over Time: April 2020 Survey to February 2022 Survey, % (95% CI)a | ||
| Overall | 1412 | 18.3 (15.4 to 21.3) | 1488 | 31.5 (28.1 to 34.8) | 13.2 (9.4 to 16.9) | |
| Age, y | ||||||
| 18–39 | 867 | 19.3 (15.3 to 23.3) | 802 | 34.8 (29.8 to 39.8) | 15.5 (10.2 to 20.9) | |
| 40–49 | 360 | 15.2 (10.1 to 20.3) | 428 | 28.7 (23.4 to 34.1) | 13.6 (6.6 to 20.5) | |
| 50+ | 185 | 19.9 (12.7 to 27.1) | 258 | 25.6 (18.7 to 32.5) | 5.7 (-2.9 to 14.3) | |
| Sex | ||||||
| Female | 798 | 21.1 (17.0 to 25.3) | 831 | 36.8 (32.2 to 41.3) | 15.6 (10.6 to 20.7) | |
| Male | 614 | 14.7 (10.7 to 18.7) | 657 | 24.8 (20.1 to 29.4) | 10.1 (4.7 to 15.5) | |
| Education | ||||||
| High school or less | 477 | 23.2 (17.1 to 29.3) | 502 | 35.1 (28.6 to 41.7) | 12.0 (4.2 to 19.7) | |
| Some college | 383 | 20.4 (15.0 to 25.9) | 414 | 37.6 (31.5 to 43.7) | 17.2 (9.9 to 24.4) | |
| Bachelor’s or more | 552 | 12.6 (8.9 to 16.3) | 572 | 23.8 (19.2 to 28.4) | 11.2 (6.7 to 15.7) | |
| Foreign born | ||||||
| Yes | 182 | 13.4 (5.2 to 21.5) | 203 | 22.6 (14.1 to 31.2) | 9.3 (-1.8 to 20.4) | |
| No | 1230 | 19.0 (15.9 to 22.2) | 1285 | 32.9 (29.3 to 36.4) | 13.8 (9.9 to 17.8) | |
| Race and ethnicityb | ||||||
| Asian | 61 | 2.6 (0.0 to 5.8) | 62 | 16.0 (4.0 to 27.9) | 13.4 (1.6 to 25.2) | |
| Black | 187 | 25.4 (16.0 to 34.9) | 204 | 41.2 (30.9 to 51.5) | 15.8 (3.5 to 28.1) | |
| Hispanic | 273 | 18.5 (10.2 to 26.8) | 320 | 27.3 (19.1 to 35.6) | 8.8% (-0.6 to 18.3) | |
| White | 823 | 17.2 (13.8 to 20.6) | 841 | 32.0 (28.0 to 36.0) | 14.8 (10.4 to 19.2) | |
| Political affiliation | ||||||
| Democrat | 460 | 12.0 (7.9 to 16.1) | 502 | 22.6 (17.5 to 27.7) | 10.6 (4.6 to 16.5) | |
| Republican | 463 | 17.2 (12.2 to 22.1) | 469 | 31.5 (25.8 to 37.3) | 14.4 (8.3 to 20.5) | |
| Other | 323 | 29.0 (21.7 to 36.4) | 371 | 42.7 (35.5 to 49.9) | 13.7 (5.5 to 21.9) | |
| Received ≤1 dose or likely to receive COVID-19 vaccine | ||||||
| Yes | 978 | 12.7 (9.7 to 15.8) | 1053 | 24.0 (20.4 to 27.6) | 11.3– (6.9 to 15.6) | |
| No | 432 | 31.0 (24.6 to 37.4) | 431 | 49.1 (42.4 to 55.8) | 18.1 (9.8 to 26.3) | |
| Age of child(ren), yc | ||||||
| 0–4 | 452 | 18.7 (13.3 to 24.1) | 438 | 29.0 (22.9–35.1) | 10.3 (3.4 to 17.2) | |
| 5–11 | 702 | 19.0 (14.6 to 23.4) | 713 | 31.6 (26.7–36.5) | 12.6 (7.2 to 18.0) | |
| 12–17 | 558 | 17.7 (13.5 to 22.0) | 624 | 33.4 (28.3–38.4) | 15.6 (9.9 to 21.4) | |
| Childhood Vaccines May Lead to Illness or Death | ||||||
|---|---|---|---|---|---|---|
| April 1–April 28, 2020 | Feb 1–Mar 30, 2022 | |||||
| Weighted Sample Size | Strongly Agree or Agree, % (95% CI) | Weighted Sample Size | Strongly Agree or Agree, % (95% CI) | Change Over Time: April 2020 Survey to February 2022 Survey, % (95% CI)a | ||
| Overall | 1412 | 18.3 (15.4 to 21.3) | 1488 | 31.5 (28.1 to 34.8) | 13.2 (9.4 to 16.9) | |
| Age, y | ||||||
| 18–39 | 867 | 19.3 (15.3 to 23.3) | 802 | 34.8 (29.8 to 39.8) | 15.5 (10.2 to 20.9) | |
| 40–49 | 360 | 15.2 (10.1 to 20.3) | 428 | 28.7 (23.4 to 34.1) | 13.6 (6.6 to 20.5) | |
| 50+ | 185 | 19.9 (12.7 to 27.1) | 258 | 25.6 (18.7 to 32.5) | 5.7 (-2.9 to 14.3) | |
| Sex | ||||||
| Female | 798 | 21.1 (17.0 to 25.3) | 831 | 36.8 (32.2 to 41.3) | 15.6 (10.6 to 20.7) | |
| Male | 614 | 14.7 (10.7 to 18.7) | 657 | 24.8 (20.1 to 29.4) | 10.1 (4.7 to 15.5) | |
| Education | ||||||
| High school or less | 477 | 23.2 (17.1 to 29.3) | 502 | 35.1 (28.6 to 41.7) | 12.0 (4.2 to 19.7) | |
| Some college | 383 | 20.4 (15.0 to 25.9) | 414 | 37.6 (31.5 to 43.7) | 17.2 (9.9 to 24.4) | |
| Bachelor’s or more | 552 | 12.6 (8.9 to 16.3) | 572 | 23.8 (19.2 to 28.4) | 11.2 (6.7 to 15.7) | |
| Foreign born | ||||||
| Yes | 182 | 13.4 (5.2 to 21.5) | 203 | 22.6 (14.1 to 31.2) | 9.3 (-1.8 to 20.4) | |
| No | 1230 | 19.0 (15.9 to 22.2) | 1285 | 32.9 (29.3 to 36.4) | 13.8 (9.9 to 17.8) | |
| Race and ethnicityb | ||||||
| Asian | 61 | 2.6 (0.0 to 5.8) | 62 | 16.0 (4.0 to 27.9) | 13.4 (1.6 to 25.2) | |
| Black | 187 | 25.4 (16.0 to 34.9) | 204 | 41.2 (30.9 to 51.5) | 15.8 (3.5 to 28.1) | |
| Hispanic | 273 | 18.5 (10.2 to 26.8) | 320 | 27.3 (19.1 to 35.6) | 8.8% (-0.6 to 18.3) | |
| White | 823 | 17.2 (13.8 to 20.6) | 841 | 32.0 (28.0 to 36.0) | 14.8 (10.4 to 19.2) | |
| Political affiliation | ||||||
| Democrat | 460 | 12.0 (7.9 to 16.1) | 502 | 22.6 (17.5 to 27.7) | 10.6 (4.6 to 16.5) | |
| Republican | 463 | 17.2 (12.2 to 22.1) | 469 | 31.5 (25.8 to 37.3) | 14.4 (8.3 to 20.5) | |
| Other | 323 | 29.0 (21.7 to 36.4) | 371 | 42.7 (35.5 to 49.9) | 13.7 (5.5 to 21.9) | |
| Received ≤1 dose or likely to receive COVID-19 vaccine | ||||||
| Yes | 978 | 12.7 (9.7 to 15.8) | 1053 | 24.0 (20.4 to 27.6) | 11.3– (6.9 to 15.6) | |
| No | 432 | 31.0 (24.6 to 37.4) | 431 | 49.1 (42.4 to 55.8) | 18.1 (9.8 to 26.3) | |
| Age of child(ren), yc | ||||||
| 0–4 | 452 | 18.7 (13.3 to 24.1) | 438 | 29.0 (22.9–35.1) | 10.3 (3.4 to 17.2) | |
| 5–11 | 702 | 19.0 (14.6 to 23.4) | 713 | 31.6 (26.7–36.5) | 12.6 (7.2 to 18.0) | |
| 12–17 | 558 | 17.7 (13.5 to 22.0) | 624 | 33.4 (28.3–38.4) | 15.6 (9.9 to 21.4) | |
To assess change over time, linear regression with cluster-robust standard errors was used to account for correlation of repeated measures and survey sampling weights. Change was deemed to be statistically significant if the 95% CI did not include 0. For clarity, statistically significant findings have been presented in boldface.
Race and ethnicity information was self-reported by panel members. Due to small sample sizes, race and ethnicity information has not been presented for American Indian or Alaska Native, Native Hawaiian or other Pacific Islander, or non-Hispanic multiracial groups.
Information about children’s ages was derived from My Household surveys, which are administered quarterly to UAS panel members to assess household demographics and composition; children’s ages are based on parental report. Children’s age categories are not mutually exclusive because parents with multiple children may be assigned to >1 category depending on the ages of their children.
Percentage of Parents Who Stated in April 2020 and February 2022 That They Strongly Agree or Agree That Vaccines Have Many Known Harmful Side Effects, Including Change Over Time
| Childhood Vaccines Have Many Known Harmful Side Effects | ||||||
|---|---|---|---|---|---|---|
| April 1–April 14, 2020 | Feb 1–Mar 30, 2022 | |||||
| Weighted Sample Size | Strongly Agree or Agree, % (95% CI) | Weighted Sample Size | Strongly Agree or Agree, % (95% CI) | Change Over Time: April 2020 Survey to February 2022 Survey, % (95% CI)a | ||
| Overall | 1412 | 26.7 (23.3 to 30.1) | 1488 | 32.8 (29.4 to 36.1) | 6.1 (2.2 to 9.9) | |
| Age, y | ||||||
| 18–39 | 867 | 28.3 (23.7 to 32.9) | 802 | 38.1 (33.1 to 43.2) | 9.8 (4.5 to 15.2) | |
| 40–49 | 360 | 24.0 (18.0 to 30.0) | 428 | 26.2 (21.1 to 31.4) | 2.2 (-5.0 to 9.4) | |
| 50+ | 185 | 24.4 (16.4 to 32.3) | 258 | 26.8 (19.8 to 33.9) | 2.5 (-6.4 to 11.4) | |
| Sex | ||||||
| Female | 797 | 29.7 (25.1 to 34.3) | 831 | 39.0 (34.4 to 43.6) | 9.3 (4.3 to 14.4) | |
| Male | 614 | 22.8 (17.9 to 27.7) | 657 | 24.8 (20.1 to 29.6) | 2.0 (-3.8 to 7.8) | |
| Education | ||||||
| High school or less | 476 | 37.5 (30.6 to 44.4) | 502 | 37.5 (30.9 to 44.0) | 0.0 (-7.7 to 7.6) | |
| Some college | 383 | 26.3 (20.3 to 32.3) | 414 | 38.1 (31.9 to 44.2) | 11.8 (4.3 to 19.2) | |
| Bachelor’s or more | 552 | 17.6 (13.2 to 22.1) | 572 | 24.7 (19.9 to 29.6) | 7.1 (2.5 to 11.7) | |
| Foreign born | ||||||
| Yes | 182 | 17.8 (9.1 to 26.4) | 203 | 28.0 (18.8 to 37.2) | 10.2 (-1.4 to 21.8) | |
| No | 1229 | 28.0 (24.4 to 31.7) | 1285 | 33.5 (29.9 to 37.1) | 5.5 (1.5 to 9.5) | |
| Race and ethnicityb | ||||||
| Asian | 61 | 6.5 (1.5 to 11.6) | 62 | 23.0 (9.4 to 36.6) | 16.5 (2.7 to 30.2) | |
| Black | 187 | 44.6 (33.6 to 55.7) | 204 | 42.9 (32.5 to 53.2) | −1.8 (-14.2 to 10.7) | |
| Hispanic | 273 | 26.8 (17.7 to 35.9) | 320 | 36.3 (27.3 to 45.2) | 9.5 (-0.8 to 19.8) | |
| White | 823 | 23.7 (19.8 to 27.7) | 841 | 29.3 (25.3 to 33.2) | 5.5 (1.1 to 9.9) | |
| Political affiliation | ||||||
| Democrat | 460 | 22.1 (16.6 to 27.6) | 502 | 24.4 (19.2 to 29.7) | 2.3 (-3.9 to 8.6) | |
| Republican | 463 | 27.6 (21.7 to 33.4) | 469 | 33.3 (27.5 to 39.2) | 5.8 (-0.9 to 12.4) | |
| Other | 323 | 33.7 (26.2 to 41.3) | 371 | 44.4 (37.1 to 51.7) | 10.7 (3.1 to 18.2) | |
| Received ≤1 dose or likely to receive COVID-19 vaccine | ||||||
| Yes | 977 | 16.6 (13.3 to 20.0) | 1053 | 25.6 (21.8 to 29.4) | 9.0 (4.4 to 13.6) | |
| No | 432 | 49.0 (42.0 to 56.0) | 431 | 49.7 (43.0 to 56.4) | 0.7 (-8.0 to 9.4) | |
| Age of childc | ||||||
| 0–4 | 451 | 24.6 (18.7 to 30.4) | 438 | 32.2 (25.8 to 38.6) | 7.6 (1.1 to 14.2) | |
| 5–11 | 702 | 25.4 (20.6 to 30.3) | 713 | 32.8 (27.9 to 37.8) | 7.4 (1.9 to 12.8) | |
| 12–17 | 558 | 27.7 (22.4 to 32.9) | 624 | 34.3 (29.2 to 39.4) | 6.6 (0.5 to 12.8) | |
| Childhood Vaccines Have Many Known Harmful Side Effects | ||||||
|---|---|---|---|---|---|---|
| April 1–April 14, 2020 | Feb 1–Mar 30, 2022 | |||||
| Weighted Sample Size | Strongly Agree or Agree, % (95% CI) | Weighted Sample Size | Strongly Agree or Agree, % (95% CI) | Change Over Time: April 2020 Survey to February 2022 Survey, % (95% CI)a | ||
| Overall | 1412 | 26.7 (23.3 to 30.1) | 1488 | 32.8 (29.4 to 36.1) | 6.1 (2.2 to 9.9) | |
| Age, y | ||||||
| 18–39 | 867 | 28.3 (23.7 to 32.9) | 802 | 38.1 (33.1 to 43.2) | 9.8 (4.5 to 15.2) | |
| 40–49 | 360 | 24.0 (18.0 to 30.0) | 428 | 26.2 (21.1 to 31.4) | 2.2 (-5.0 to 9.4) | |
| 50+ | 185 | 24.4 (16.4 to 32.3) | 258 | 26.8 (19.8 to 33.9) | 2.5 (-6.4 to 11.4) | |
| Sex | ||||||
| Female | 797 | 29.7 (25.1 to 34.3) | 831 | 39.0 (34.4 to 43.6) | 9.3 (4.3 to 14.4) | |
| Male | 614 | 22.8 (17.9 to 27.7) | 657 | 24.8 (20.1 to 29.6) | 2.0 (-3.8 to 7.8) | |
| Education | ||||||
| High school or less | 476 | 37.5 (30.6 to 44.4) | 502 | 37.5 (30.9 to 44.0) | 0.0 (-7.7 to 7.6) | |
| Some college | 383 | 26.3 (20.3 to 32.3) | 414 | 38.1 (31.9 to 44.2) | 11.8 (4.3 to 19.2) | |
| Bachelor’s or more | 552 | 17.6 (13.2 to 22.1) | 572 | 24.7 (19.9 to 29.6) | 7.1 (2.5 to 11.7) | |
| Foreign born | ||||||
| Yes | 182 | 17.8 (9.1 to 26.4) | 203 | 28.0 (18.8 to 37.2) | 10.2 (-1.4 to 21.8) | |
| No | 1229 | 28.0 (24.4 to 31.7) | 1285 | 33.5 (29.9 to 37.1) | 5.5 (1.5 to 9.5) | |
| Race and ethnicityb | ||||||
| Asian | 61 | 6.5 (1.5 to 11.6) | 62 | 23.0 (9.4 to 36.6) | 16.5 (2.7 to 30.2) | |
| Black | 187 | 44.6 (33.6 to 55.7) | 204 | 42.9 (32.5 to 53.2) | −1.8 (-14.2 to 10.7) | |
| Hispanic | 273 | 26.8 (17.7 to 35.9) | 320 | 36.3 (27.3 to 45.2) | 9.5 (-0.8 to 19.8) | |
| White | 823 | 23.7 (19.8 to 27.7) | 841 | 29.3 (25.3 to 33.2) | 5.5 (1.1 to 9.9) | |
| Political affiliation | ||||||
| Democrat | 460 | 22.1 (16.6 to 27.6) | 502 | 24.4 (19.2 to 29.7) | 2.3 (-3.9 to 8.6) | |
| Republican | 463 | 27.6 (21.7 to 33.4) | 469 | 33.3 (27.5 to 39.2) | 5.8 (-0.9 to 12.4) | |
| Other | 323 | 33.7 (26.2 to 41.3) | 371 | 44.4 (37.1 to 51.7) | 10.7 (3.1 to 18.2) | |
| Received ≤1 dose or likely to receive COVID-19 vaccine | ||||||
| Yes | 977 | 16.6 (13.3 to 20.0) | 1053 | 25.6 (21.8 to 29.4) | 9.0 (4.4 to 13.6) | |
| No | 432 | 49.0 (42.0 to 56.0) | 431 | 49.7 (43.0 to 56.4) | 0.7 (-8.0 to 9.4) | |
| Age of childc | ||||||
| 0–4 | 451 | 24.6 (18.7 to 30.4) | 438 | 32.2 (25.8 to 38.6) | 7.6 (1.1 to 14.2) | |
| 5–11 | 702 | 25.4 (20.6 to 30.3) | 713 | 32.8 (27.9 to 37.8) | 7.4 (1.9 to 12.8) | |
| 12–17 | 558 | 27.7 (22.4 to 32.9) | 624 | 34.3 (29.2 to 39.4) | 6.6 (0.5 to 12.8) | |
To assess change over time, linear regression with cluster-robust standard errors was used to account for correlation of repeated measures and survey sampling weights. Change was deemed to be statistically significant if the 95% CI did not include zero. For clarity, statistically significant findings have been presented in boldface.
Race and ethnicity information was self-reported by panel members. Due to small sample sizes, race and ethnicity information has not been presented for American Indian or Alaska Native, Native Hawaiian or other Pacific Islander, or non-Hispanic multiracial groups.
Information about children’s ages was derived from My Household surveys, which are administered quarterly to UAS panel members to assess household demographics and composition; children’s ages are based on parental report. Children’s age categories are not mutually exclusive because parents with multiple children may be assigned to >1 category depending on the ages of their children.
Discussion
In this national sample, the proportion of parents concerned about the safety and side effects of routine childhood vaccines increased significantly between April 2020 and March 2022; this trend was also observed for most parent subgroups. However, parent confidence in the benefits and effectiveness of childhood vaccines remained high. Our findings underscore the important role of pediatricians in addressing parents’ concerns about childhood vaccines, as they are highly trusted by parents about vaccinations7,8 and can address vaccine hesitancy.9,10 Pediatricians should therefore ask hesitant parents about their particular concerns and be prepared to address safety concerns.
Study strengths included the use of a nationally representative sample and the ability to analyze trends using data frequently collected since the beginning of the pandemic. Limitations included: generalizability of online panel data (although UAS recruitment methods and use of survey weights in analyses should mitigate this bias), insufficient sample sizes for certain racial and ethnic groups, and inability to determine if concern was higher or lower for specific childhood vaccines or the exact factors causing the observed rise in concern.
We conclude that parent concern about the safety of routine childhood vaccines has increased nationally since the start of the pandemic.
Dr Shah conceptualized and designed the study, drafted the initial manuscript, and reviewed and revised the manuscript; Drs Szilagyi, Shetgiri, Delgado, Dudovitz, and Vizueta conceptualized and designed the study and reviewed and revised the manuscript; Mr Vangala carried out the initial analyses and reviewed and revised the manuscript; Drs Thomas and Kapteyn and Ms Darling conceptualized and designed the study, obtained funding, coordinated and supervised data collection, and critically reviewed the manuscript for important intellectual content; and all authors approved the final manuscript as submitted and agree to be accountable for all aspects of the work.
FUNDING: This work was supported by the University of Southern California and by Federal funds from the National Center for Advancing Translational Sciences, NIH, through the Clinical and Translational Science Awards Program (grant UL1TR001881), the National Institute on Aging (grant 5U01AG054580-03), and the National Science Foundation (grant 2028683).The sponsors had no role in the design and conduct of the study collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; or decision to submit the manuscript for publication. Funded by the National Institutes of Health (NIH).
CONFLICT OF INTEREST DISCLOSURES: The authors have indicated they have no potential conflicts of interest relevant to disclose.
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