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Year : 2022  |  Volume : 67  |  Issue : 1  |  Page : 92
Online information-seeking behavior for allergies and its association with COVID-19 vaccine-hesitancy in India: An info-epidemiologic study

1 Department of Physiology, Fakir Mohan Medical College and Hospital, Balasore, Odisha, India
2 Department of Dermatology, College of Medicine and Sagore Dutta Hospital, Kolkata, West Bengal, India
3 Department of Physiology, Raiganj Government Medical College and Hospital, West Bengal, India

Date of Web Publication19-Apr-2022

Correspondence Address:
Indrashis Podder
Department of Dermatology, College of Medicine and Sagore Dutta Hospital, Kolkata - 700 058, West Bengal
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/ijd.ijd_593_21

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Background: Vaccine-hesitancy is an important obstacle to attain herd-immunity against COVID-19. Undue fears about adverse effects like allergic reactions may be an important reason for vaccine-hesitancy. Objectives: To assess the online information-seeking behavior of Indian internet users regarding 'allergies' and determine its association with COVID-19 vaccine-hesitancy. Methods: We conducted a Google trend analysis to obtain the relative search volume (RSV) for keywords—'skin allergy,' 'drug allergy,' 'food allergy,' 'vaccine allergy,' 'contact dermatitis,' and 'allergy' using a public domain We further obtained state-wise data and statistically analyzed it to assess any association with vaccine-hesitancy. Results: Higher RSV was found for 'vaccine allergy' after the advent of COVID-19 vaccines, showing the steepest peak. 'Skin allergy' showed two peaks. The first peak was after the advent of COVID-19 pandemic and second peak was after introduction of vaccines. RSV of 'contact dermatitis' remained unchanged. Eastern and North-Eastern states showed the highest RSV for 'skin' and 'vaccine' allergies. Literacy rate showed a significant positive correlation with vaccination, whereas vaccine-hesitancy was inversely proportional to RSV for 'allergy.' Conclusion: Increased online information-seeking behavior is demonstrated by Indians regarding various 'allergies,' particularly after the advent of COVID-19 vaccines. Literacy was directly proportional to vaccination status, whereas vaccine-hesitancy was inversely proportional to search-volume for 'allergy.'

Keywords: Allergy, COVID-19 vaccine, information-seeking behavior, online, vaccine-hesitancy

How to cite this article:
Mondal H, Podder I, Mondal S. Online information-seeking behavior for allergies and its association with COVID-19 vaccine-hesitancy in India: An info-epidemiologic study. Indian J Dermatol 2022;67:92

How to cite this URL:
Mondal H, Podder I, Mondal S. Online information-seeking behavior for allergies and its association with COVID-19 vaccine-hesitancy in India: An info-epidemiologic study. Indian J Dermatol [serial online] 2022 [cited 2023 Dec 8];67:92. Available from:

   Introduction Top

The ongoing COVID-19 pandemic, caused by SARS-CoV-2 virus, has accounted for 30, 670, 494 confirmed cases and more than 404,341 deaths in India as on 07.07.2021.[1] With no cure in sight, vaccines remain our best option to reduce the intensity and severity of this health emergency. Recently, several vaccine candidates have been introduced with varying modes of action.[2] The goal is to vaccinate all people throughout the world to achieve population-based 'herd-immunity' that would help to control this pandemic.[3] However, many people are unwilling to receive their vaccines, thereby reducing our chances to realize the goal. This situation is even more critical in densely populated countries like India, with inadequate health facilities and shortage of trained manpower.

One of the prime reasons for vaccine-hesitancy is the fear of adverse effects, especially vaccine-induced allergic reactions. Vaccine-induced allergic reactions are of two types—early hypersensitivity reactions including anaphylaxis and delayed reactions. Sporadic cases of hypersensitivity including anaphylaxis have been reported to Pfizer/BioNTech BNT162B2 or the Moderna mRNA-1273 mRNA vaccines, possibly due to their excipients PEG and/or polysorbate 80.[4] As with any other drug, life-threatening anaphylaxis may occur due to these vaccines even in the absence of previous allergic disorders, and the current estimate is 2.5–11.1 cases per 1 million doses for the mRNA-1273 and BNT162b2 vaccines, respectively.[5] Delayed hypersensitivity reactions include local injection site reactions (Covid-arm), urticarial eruptions, and morbiliform eruptions, none of them being life-threatening or treatment unresponsive.[6] Thus, serious adverse effects seem rare with the current COVID-19 vaccines, and a favorable risk-benefit ratio has prompted the EAACI/WAO to recommend COVID-19 vaccination in all individuals, the only contraindication being a known allergy to one of the vaccine components and/or severe allergic reaction to the first dose.[2],[3]

Despite strong recommendations in favor of vaccination, vaccine hesitancy has become a serious concern in India, as it impedes the development of 'herd-immunity.' It is vital to have an idea about the reasons for vaccine-hesitancy to address these concerns and promote mass-vaccination. We hypothesized that concern of allergic reactions may be such a reason, although no serious adverse effects, including anaphylactic reactions, have been reported due to the currently available COVID-19 vaccines in India.[7] We conducted a Google trend analysis to obtain an idea about the search strategy of Indians and their information-seeking behavior in this context, with the idea that volume of search for perceived allergic reactions due to vaccine is directly proportional to vaccine-hesitancy. Previous studies have highlighted the role of Google searches to monitor and predict peoples' search.[8]

Thus, we aimed to correlate the search strategy with vaccination status across India and evaluate the underlying factors. We hope that our findings will help the policy-makers to implement appropriate public-health measures in this regard.

   Materials And Methods Top


For this study, we audited data from a public domain ( This website does not divulge any identification data of any internet user. The website provides the trend data as a comma separated value (.CSV) for further analysis of the data. There were no human research participants in this study. Hence, this study does not require any clearance from the Institutional Ethics Committee as per prevalent rules in the region from where the study was conducted.

Keywords selection

According to our research question, we fixed five phrases to be used in the trend search. We consulted three experienced dermatologists and two information technology engineers with expertise in search engineer optimization for selection of the keywords. Adequate anonymity was ensured. The aim was to find words or phrases related to allergy and related diseases that may be searched by a common internet user. The final list of the five phrases were—skin allergy, drug allergy, food allergy, vaccine allergy, and contact dermatitis. For finding overall allergy-related search trend, we searched only “allergy” separately with the same setting.

Data collection

For data collection, we used a personal computer (Asus VivoBook max X541N) running on Windows 10 operating system. We used a catch and history-cleared internet browser (Mozilla Firefox version 88.01) for searching the phrases on the Google trends website on 04/07/2021. The phrases were searched at a time and a comparative trend data is shown as a result. We searched the global data using the region as “India,” time range as “01/07/2018–30/06/2021,” categories of search as “All categories,” and search type as “Web Search.” After appearance of the result of interest over time, we downloaded the.CSV file for further analysis. Vaccination status was obtained from and state-wise literacy rate was obtained from; both were freely available data in public domain.[9],[10]

Statistical analysis

We expressed the data obtained from Google trends in descriptive statistics and visualized it with suitable trend lines and geographical distribution. The data was handled in Microsoft Excel® 2010 (Microsoft Inc, USA) and statistical analysis was carried out in GraphPad Prism 6.01 (GraphPad Software, CA, USA). We compared categorical data (trend RSV for 6-month period) statistically by Chi-square test (comparing the observed with an expected equal distribution in groups). For finding correlation between allergy-related relative search volume (RSV) and percentage of vaccinated population in states, we used Spearman's correlation coefficient. For any statistical test, P was considered statistically significant is it is <0.05.

   Results Top

The search volume for 3 years (July 2018–June 2021), before and during the COVID-19 pandemic is shown in [Figure 1]. The highest search volume over the period of July 2018–June 2021 was for Skin allergy, followed by food allergy, contact dermatitis, drug allergy, and then vaccine allergy (P <.01).
Figure 1: Relative search volume on allergies over time (July 2018–June 2021). Footnote: Weekly relative search volumes (RSV) were added to get a RSV for a month. Statistical analysis: χ2 = 1648, P < 0.0001

Click here to view

We observed two peaks of search volume for “skin allergy”—one in May 2020 (with an overall increase in January–June, 2020 RSV) and another in May 2021 (with an overall increase in January–June, 2021 RSV), χ2 (5, N = 9976) = 186.3, P<.01. Search volume of “vaccine allergy” steeply increased in April 2021 with an overall increase in January–June, 2021 RSV, χ2 (5, N = 558) = 1589, P<.01.

Similarly, we noted higher volume of search for drug allergy (χ2 [5, N = 686] = 17.03, P < .01), and food allergy (χ2 [5, N = 2104] = 40.10, P < .01) in Jan–June, 2021. However, search volume of contact dermatitis remained similar to previous timeline (χ2 [5, N = 1048] = 9.65, P = 0.09).

Indian states according to search volume of skin allergy are shown in [Figure 2]. Nagaland, Arunachal Pradesh, Puducherry, Uttarakhand, Meghalaya, Chandigarh, Himachal Pradesh, Goa, and Chhattisgarh were among the top searching states. Indian states according to search volume of vaccine allergy are shown in [Figure 3]. Manipur, Bihar, West Bengal, Kerala, and Assam were the top five states searching about vaccine allergy. For other phrases, there was availability of very few data for generation of heat map.
Figure 2: Indian state-wise relative search volume on skin allergy. Footnote: The map was generated with Google trends relative search volume data on free spreadsheet (Excel) software available on

Click here to view
Figure 3: Indian state-wise relative search volume on vaccine allergy. Footnote: The map was generated with Google trends relative search volume data on free spreadsheet (Excel) software available on

Click here to view

We found a positive correlation (Spearman's correlation coefficient (rs) = 0.33, 95% CI: -0.025 to 0.604, P = 0.03) between the percentage of vaccinated population and RSV of “allergy” among Indian states [Figure 4]. There was also a positive correlationbetween the literacy rate and the percentage of vaccination (rs = 0.52, 95% CI: 0.2170 to 0.7377, P < .01) [Figure 5].
Figure 4: Correlation between percentage of vaccinated population and relative search volume for allergy. Footnote: Spearman's correlation coefficient (rs) = 0.33, 95% Confidence interval: -0.02503–0.6044, P = 0.03. Relative search volume of allergy in Indian states (obtained from 05/07/2021) is presented in Y axis and percentage of vaccinated population (vaccination data obtained from population data obtained from 05/07/2021) is presented in X axis

Click here to view
Figure 5: Correlation between literacy rate and percentage of vaccination. Footnote: Spearman's correlation coefficient (rs) = 0.52, 95% Confidence interval: 0.2170–0.7377, P = 0.0007. Percentage of vaccinated poulation (obtained from 05/07/2021) is presented in Y axis and percentage of literacy of population (obtained from on 05/07/2021) is presented in X axis

Click here to view

   Discussion Top

Information-seeking behavior

The highest RSV was obtained for 'skin allergy,' which showed two peaks in May 2020 and May 2021. The first peak co-incided with emergence of COVID-19 infection and its declaration as a global pandemic by the WHO in March 2020.[11] The second peak coincided with the availability of different vaccines in the national and International markets. Search for 'vaccine allergy' also increased steeply during the same period. The search for 'drug allergy' and 'food allergy' also increased after vaccine arrival (Jan–June 2021). A study from Bangladesh also reported higher search trends for COVID-19 related data during during March–April 2020, but declined gradually after June 2020. However, our search pattern was maintained with subsequent peaks.[8]

Interestingly, the RSV for skin allergy was also high in the pre-COVID time (July 2018–February 2020), thus indicating a persistent knowledge-gap regarding 'skin allergy,' which increased after the advent of COVID-19. So, we need to arrange future education programs involving specialists like dermatologists and allergologists to increase awareness on this topic.

Another interesting feature was the stability of RSV regarding 'contact dermatitis' without any influence of COVID-19 pandemic or its vaccine. This is surprising, as several cases of 'contact dermatitis' has been reported post-COVID to various protective equipments such as masks, gloves, and sanitizers.[12] However, our population seems unaware of these reports or they included these searches under the broad term 'skin allergy.' These authors recommend health program for education regarding 'contact dermatitis' and their preventive and management options.

State-wise distribution of data

RSV pattern for 'skin allergy and 'vaccine allergy' showed higher searches from the Eastern, Central, and North-Eastern India [Figure 2] and [Figure 3] This may indicate a lack of trained healthcare personnel in these regions, which prompted people from these regions to look-up the internet for information instead of their consulting physicians. These authors recommend further epidemiologic studies to assess the distribution of healthcare personnel in various parts of India and take appropriate measures to bridge this gap.

Information-seeking behavior and vaccine-hesitancy

We found a significant positive correlation between percentage of vaccination and RSV for 'allergy.' Thus, vaccine-hesitancy (unwillingness to receive vaccine) is inversely proportional to RSV for 'allergy,' defying our hypothesis. This may be attributed to more accurate information obtained from the internet, than heresay about various allergic adverse-effects and contraindications of vaccine (less RSV for allergy). So, in our study, most people possibly referred to the internet to educate themselves. An American study demonstrated higher vaccine-hesitancy in those regions with higher RSV for vaccine-associated infertility, whereas our study demonstrated an inversely proportional relation between vaccine-hesitancy and RSV for 'allergy.'[13] We need more epidemiologic and descriptive studies to corroborate our findings.

We also detected a significant positive correlation between literacy rate and percentage of vaccination, that is vaccine-hesitancy is directly linked to illiteracy. So, literacy should be promoted to increase awareness among people and take rational decisions best for themselves (e.g., vaccination), instead of paying heed to rumours and misconceptions. This is an important consideration to remain prepared for similar future pandemics.


Our study has several limitations; we were limited to Googles' search engine, so we failed to capture data from alternative search engines (e.g. Yahoo, Bing). Only search result in English was considered, while few data were inadequate at the level of Google trends website and had to be ignored. However, this is a common limitation of studies with Google search trends.[14] Besides, online health search behavior does not necessarily correlate with vaccine-hesitancy and users may change their mind afterwards. Another important limitation was the absence of demographic details on Google Trends such as age, sex, race, education status, and income. Furthermore, this is a geographical ecological study that used available data on public domain. Hence, it may have several biases including 'ecological fallacy' that was beyond our control.[15]

   Conclusions Top

The RSV for 'skin allergy' was the highest, which showed two peaks coinciding with advent of COVID-19 pandemic and its vaccines, respectively. The RSV of 'vaccine-allergy' peaked after introduction of vaccines. The search for 'contact dermatitis' remained stable irrespective of the COVID-19 pandemic. The RSV was the highest for Eastern and North-Eastern India. Vaccine-hesitancy was inversely proportional to RSV for 'allergy,' whereas literacy rate demonstrated a significant positive correlation with vaccination status.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

   References Top

Coronavirus Cases. Worldometer. Available from: [Last accessed on 2021 Jul 07].  Back to cited text no. 1
Turner PJ, Ansotegui IJ, Campbell DE, Cardona V, Ebisawa M, Yehia EG, et al. COVID-19 vaccine-associated anaphylaxis: A statement of the World Allergy Organization Anaphylaxis Committee. World Allergy Organ J 2021;14:100517.  Back to cited text no. 2
Sokolowska M, Eiwegger T, Ollert M, Torres MJ, Barber D, Del Giacco S, et al. EAACI statement on the diagnosis, management and prevention of severe allergic reactions to COVID-19 vaccines. Allergy 2021;76:1629-39.  Back to cited text no. 3
Kim MA, Lee YW, Kim SR, Kim JH, Min TK, Park HS, et al. COVID-19 Vaccine-associated anaphylaxis and allergic reactions: Consensus statements of the KAAACI Urticaria/Angioedema/Anaphylaxis Working Group. Allergy Asthma Immunol Res 2021;13:526-44.  Back to cited text no. 4
Blumenthal KG, Robinson LB, Camargo CA, Shenoy ES, Banerji A, Landman AB, et al. Acute allergic reactions to mRNA COVID-19 vaccines. JAMA 2021;325:1562-5.  Back to cited text no. 5
McMahon DE, Amerson E, Rosenbach M, Lipoff JB, Moustafa D, Tyagi A, et al. Cutaneous reactions reported after Moderna and Pfizer COVID-19 vaccination: A registry-based study of 414 cases. J Am Acad Dermatol 2021;85:46-55.  Back to cited text no. 6
Vaccine drive. Ministry of Health and Family Welfare, Government of India. Available from: [Last accessed on 2021 Jul 07].  Back to cited text no. 7
Ahamad MG, Ahmed MU, Uden DR. Public search interests related to COVID-19: Insights from Google search trends in Bangladesh. medRxiv 2021.  Back to cited text no. 8
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Number of literates and literacy rate by sex. Office of the Registrar General & Census Commissioner, India. Available from: [Last accessed on 2021 Jul 05].  Back to cited text no. 10
Mental Health and Psychosocial Considerations During the COVID-19 Outbreak. Geneva: World Health Organization. Available from: /10665/331490/WHO-2019-nCoV-MentalHealth-2020.1-eng.pdf. [Last accessed on 2021 Jul 07].  Back to cited text no. 11
Dowdle TS, Thompson M, Alkul M, Nguyen JM, Sturgeon ALE. COVID-19 and dermatological personal protective equipment considerations. Proc (Bayl Univ Med Cent) 2021;34:469-72.  Back to cited text no. 12
Diaz P, Reddy P, Ramasahayam R, Kuchakulla M, Ramasamy R. COVID-19 vaccine hesitancy linked to increased internet search queries for side effects on fertility potential in the initial rollout phase following Emergency Use Authorization. Andrologia 2021:e14156.  Back to cited text no. 13
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  [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]


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