ABSTRACT
Recent laboratory and observational studies have demonstrated that the COVID-19 vaccine effectiveness wanes over time. In response, several jurisdictions have authorized the administration of booster doses. Since August 13, 2021, Puerto Rico has administered 540,140 booster shots. We used data collected and made public by the Puerto Rico Department of Health (PRDH) to evaluate the effectiveness of four different booster regimens at preventing SARS-CoV-2 laboratory confirmed infections and adverse COVID-19 outcomes. Specifically, we analyzed data from all 115,995 SARS-CoV-2 infections occurring since the vaccination process commenced on December 15, 2020. We combined vaccination status, SARS-CoV-2 test results, and COVID-19 hospitalizations and deaths data, and fit a statistical model that adjusted for time-varying incidence rates and age group, to estimate time-varying vaccine effectiveness against infection and adverse outcomes. We find that, after 6 months, the mRNA-1273 and BNT162b2 effectiveness against infection wanes substantially to 61% (58%-63%) and 36% (34%-39%), respectively, while the Ad26.COV2.S wanes to 35% (31%-39%) after two months. However, after a booster shot of the corresponding initial vaccine manufacturer, effectiveness increased to 87% (83%-91%) and 82% (79%-85%) for mRNA-1273 and BNT162b2, respectively. The effectiveness for Ad26.COV2.S followed by either a mRNA-1273 or BNT162b2 booster increased to 88% (71%-100%), substantially higher than 65% (59%-70%), the peak effectiveness reached with just one shot. We also found that heterologous booster regimens restored effectiveness. Furthermore, we did not observe waning after two months of the booster shot. Finally, we found that all booster regimens provided increased protection against COVID-19 hospitalizations and deaths. Code and data to reproduce the analyses are provided here: https://github.com/rafalab/booster-eff-pr.
ABSTRACT
BackgroundAs of October 1, 2021 2,217,547 individuals were fully vaccinated against COVID-19 in Puerto Rico. Since the vaccination process commenced on December 15, 2020 111,052 laboratory-confirmed SARS-CoV-2 infections have been reported. These data permitted us to quantify the benefits of the immunization campaign and to compare effectiveness of the mRNA-1273 (Moderna), BNT162b2 (Pfizer), and Ad26.COV2.S (J&J) vaccines. MethodsDepartment of Health databases holding vaccination status, SARS-CoV-2 test results, and COVID-19 hospitalizations and deaths were integrated. We fit a statistical model that adjusted for time-varying incidence rates and age to estimate vaccine effectiveness and hospitalization and death relative risks. Code and data are provided here: https://github.com/rafalab/vax-eff-pr. ResultsAt the peak of their protection, mRNA-1273, BNT162b2, and Ad26.COV2.S had an effectiveness of 90% (88%-91%), 87% (85%-89%), and 58% (51%-65%), respectively. After four months, effectiveness waned to about 70%, 60%, and 30%. We found no evidence that effectiveness was different after the Delta variant became dominant. For those infected, the vaccines provided further protection against hospitalization and deaths across all age groups. All vaccines had a lower effectiveness for those over 85 years, with a larger decrease for the Ad26.COV2.S vaccine. Overall, thousands of hospitalizations and deaths were avoided thanks to the vaccines. ConclusionsThe mRNA-1273 and BNT162b2 vaccines were highly effective across all age groups. They were still effective after four months although the protection waned. The Ad26.COV2.S vaccine was effective but to a lesser degree, especially for older age groups.
ABSTRACT
Official COVID-19 mortality statistics are strongly influenced by local diagnostic capacity, strength of the healthcare and vital registration systems, and death certification criteria and capacity, often resulting in significant undercounting of COVID-19 attributable deaths. Excess mortality, which is defined as the increase in observed death counts compared to a baseline expectation, provides an alternate measure of the mortality shock - both direct and indirect - of the COVID-19 pandemic. Here, we use data from civil death registers from a convenience sample of 90 municipalities across the state of Gujarat, India, to estimate the impact of the COVID-19 pandemic on all-cause mortality. Using a model fit to weekly data from January 2019 to February 2020, we estimated excess mortality over the course of the pandemic from March 2020 to April 2021. We estimated 21,300 [95% CI: 20,700, 22,000] excess deaths across these municipalities in this period, representing a 44% [95% CI: 43%, 45%] increase over the expected baseline. The sharpest increase in deaths in our sample was observed in late April 2021, with an estimated 678% [95% CI: 649%, 707%] increase in mortality from expected counts. The 40 to 65 age group experienced the highest increase in mortality relative to the other age groups. We found substantial, yet similar, increases in mortality for males and females. Our excess mortality estimate for these 90 municipalities, representing approximately 5% of the states population, exceeds the official COVID-19 death count for the entire state of Gujarat, even before the delta wave of the pandemic in India peaked in May 2021. Prior studies have concluded that true pandemic-related mortality in India greatly exceeds official counts. This study, using data directly from the first point of official death registration data recording, provides incontrovertible evidence of the high excess mortality in Gujarat from March 2020 to April 2021.
