In a recent study published in npj Vaccines, researchers assessed the association between Pfizer-BioNTech’s severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) BNT162b2 messenger ribonucleic acid (mRNA) vaccination and the incidence of post-coronavirus disease 2019 (COVID-19) symptoms among Israeli adults.
The continual emergence of SARS-CoV-2 VOCs (variants of concern) has led to significant morbidity and mortality across the globe. Several COVID-19 vaccines have been developed to curtail SARS-CoV-2 transmission and mitigate the associated disease burden.
However, the efficacy of COVID-19 vaccines concerning the development of persistent or long COVID symptoms needs further investigation.
About the study
In the present study, researchers determined whether BNT162b2 vaccination was associated with the incidence of long COVID symptoms.
Individuals tested for COVID-19 by RT-PCR (reverse transcription polymerase chain reaction) between March 15, 2020, and November 15, 2021, from three North Israel hospitals, were sent invitations to participate in the present study and filled out online questionnaires between 16 July and 18 November 2021. SMS (short message service) comprising the invitation and online survey links were sent to all individuals.
The modified ISARIC (international severe acute respiratory and emerging infection consortium) questionnaires included data on the (i) socio-demographical status (sex, age, residence, race, income, and educational levels), (ii) health status [BMI (body mass index) values and presence of chronic disorders], (iii) clinical symptoms experienced at the time of SARS-CoV-2 infection diagnosis and during filling out of questionnaires, (iv) COVID-19 test reports, (v) vaccination data, including the status of vaccination, doses administered, vaccine type and vaccination dates.
The prime study outcome was the fraction of study participants who reported particular health outcomes based on the status of SARS-CoV-2 infection and vaccination status. The questionnaires were available in four languages: Arabic, Hebrew, English, and Russian, and binomial regression modeling was used to compare vaccinated individuals with unvaccinated and uninfected individuals, concerning long COVID symptoms.
Data adjustments were made for age, time differences from symptom onset to survey responses, and the number of patients with asymptomatic COVID-19 between the groups. In addition, an age-stratified analysis was performed to determine potential age-specific effects.
Results and discussion
In total, 79,482 individuals were invited to participate in the study, of which, only 4.5% (n=3,572) adults agreed to participate. Prior COVID-19 history was reported by 1125 participants, whereas the remaining 2447 did not have any SARS-CoV-2 exposure. The team excluded 174 SARS-CoV-2-infected adults from the analysis since the vaccination status was not reported by them.
Out of 951 SARS-CoV-2-infected individuals, 67% (n=637) had received COVID-19 vaccinations, 340 individuals (36%) had received single vaccination, and 294 individuals (31%) had received ≥2 vaccine doses (of which, 27 individuals had received booster (third) vaccinations). Out of 2,447 SARS-CoV-2-naive adults without prior COVID-19 history, 0.9% (n=21), 49% (n=1195), and 30% (n=744) had received single, double and triple doses, respectively, and the remaining 20% were unvaccinated.
Unvaccinated adults were younger than those who had received single and double vaccinations, and pre-existing chronic disorders were reported more frequently among vaccinated adults. Out of the 951 SARS-CoV-2-infected adults, 67% (n=636) reported ≥1 symptom at the time of SARS-CoV-2 testing. Among unvaccinated participants, 69% reported ≥1 symptom at the time of COVID-19 diagnosis, versus 74% and 57% of participants who received single and double COVID-19 vaccinations, respectively.
Out of 951 SARS-CoV2-infected adults, 35% (n=337) did not completely recover from the initial SARS-CoV-2 infection at the follow-up assessment. The most commonly reported long COVID symptoms were fatigue, headache, limb weakness, and persistent muscular pain reported in 22%, 20%, 13%, and 10% of participants, respectively.
In comparison to unvaccinated individuals, the likelihood of reporting eight and seven of the top 10 most commonly reported SARS-CoV-2 infection symptoms was 36% to 73% and 50% to 81% lower among doubly vaccinated individuals, respectively. The likelihood of experiencing persistent muscle pain, limb weakness, fatigue, and headache were lower by 66%, 62%, 62%, and 50% among doubly vaccinated adults, with risk ratios (RRs) of 0.3, 0.4, 0.4, and 0.5, respectively.
The age-stratified analysis showed differences in reported COVID-19 symptoms primarily observed among elder individuals aged >60 years, which may be since young individuals have a greater physiological reserve and can therefore recover on their own, which is not seen in the elderly.
Overall, the study findings highlighted the protective effects of BNT162b2 mRNA vaccinations against long COVID symptoms.