The present study reported the attitude and experiences of Malaysian adults following six months of the National Vaccination Program for COVID-19. The findings showed that the general attitudes towards the ongoing vaccination program were positive. There was a high level of adherence to SOP after being vaccinated. The confidence level in the crucial role of vaccines in facing this pandemic was high. However, there were differences in the experiences of the vaccinated individuals regarding prevalence and number of side effects explained by demographic and vaccine type data.
Out of 428 respondents, the majority (71.1%) were from the younger age group below 45. Although the survey was available in two Malay and English languages, most respondents were Malays (92.1%), which is expected as the major race in Malaysia. With the higher number of female respondents (66.4%), it was expected to have more non-smokers in the survey since most smokers in Malaysia were males . However, it was noted that 6.5% of current smokers have also reported their attitude towards vaccines which is important since they are at higher risk of COVID-19 complications. Furthermore, our findings revealed that approximately 21% of respondents had chronic diseases that may put them at higher risk of COVID-19 infection and complications, implying a need for special care considerations in this patient population .
The majority (86%) of the respondents who attended college or university supported the findings that vaccine acceptance was higher in people with higher education levels and higher income . Digital literacy could be one of the factors to this outcome since it is strongly associated with the utility of information and communications technologies among older adults . However, it is essential to note that the national vaccination program has mainly vaccinated health care practitioners, non-health front liners (e.g., police officers), people with comorbidities, and the elderly population until the completion of the present study. It has been proposed that high-risk populations and disadvantaged groups should be prioritized for vaccination while promoting equity and social justice .
Most respondents (98.6%) registered for vaccines through the government application MySejahtera or their employers. Nevertheless, we need to acknowledge that there were segments in the Malaysian population manually registering at the vaccination centers or lacking internet access and digital literacy. To achieve herd immunity, greater coverage of technology delivering accurate information will reflect collective attitudes and experiences towards vaccines through communication campaigns by the health authorities (Lin et al., 2020). With 32% of respondents having contracted COVID-19 infection or had family members/relatives diagnosed with the disease, these experiences might have influenced our study's positive attitude towards vaccines. Prior to vaccine availability, a study reported that individuals with COVID-19 infection or their family members did not accept vaccines better than others who had no such experiences . Nevertheless, the influence of personal COVID-19 experience toward vaccines was inconclusive .
Less than 5% reported concerns about registering or receiving COVID-19 vaccination (Figure 1). The most common concern was related to the vaccine safety reported previously to hinder vaccine uptake to a certain extent . Some other issues were related to the perceived effectiveness of the vaccine, and willingness to protect others had been reported to influence the acceptance of COVID-19 vaccines . Vaccine hesitancy is a complex global issue involving differences in sociodemographic and external factors, and thus tailored strategies to local intervention must be implemented in the specific population [16,22]. Community intervention has been shown to improve the influenza vaccination rate in specific populations by addressing their concerns . The findings showed a statistically significant difference between males and females on their perception of receiving accurate and sufficient vaccine-related information, where males frequently believed that they did not receive adequate vaccine-related information. This point could be of relevant consideration in the vaccine advocacy initiatives.
Most of our respondents (97.9%) reported good to very high confidence levels towards vaccine effectiveness. However, about one-fifth did not believe that they received accurate and sufficient information regarding COVID-19 vaccines. The main sources of information about COVID-19 vaccination were the official Ministry of Health website and MySejahtera application (53.7%), followed by social media (22.1%) and others. Transparency in disseminating vaccines and COVID-19 updates by government health officials is vital to prevent distrust towards vaccines. It has been reported that different countries had different COVID-19 vaccines acceptance rates. However, Malaysia was among the highest (94.3%) other than Ecuador (97.0%), Indonesia (93.3%), and China (91.3%), whereas the lowest acceptance rates were found in Kuwait (23.6%), Jordan (28.4%), Italy (53.7), Russia (54.9%), Poland (56.3%), US (56.9%), and France (58.9%) . These have also been linked to the level of trust towards information from government sources and employer’s advice , particularly addressing newly developed vaccines with expedited development or approval with political orientation and interference .
Most respondents reported high adherence to standard operating procedures (SOP) to prevent COVID-19 infection. However, a small percentage (8.4%) did not know COVID-19 infection risk following complete vaccination and its severity between vaccinated and unvaccinated individuals. This data indicated that the circulation of the latest information has not effectively reached some communities to control the pandemic effectively. We also found that 1.2% felt safer removing masks frequently after getting vaccinated. In addition, a study reported that people with a positive attitude towards vaccines were more likely to follow strict SOPs than those with negative attitudes . Despite the availability of 13 types of COVID-19 vaccines worldwide with efficacy ranging between 50-95%, preventive behaviors including physical distancing and wearing masks must be continuously enforced by individuals and authorities until effective vaccines are available to overcome the emergence of mutations with coronavirus variants . Health literacy and digital health literacy have been reported independently associated with overall compliance with basic preventive practices .
Our respondents received vaccines from three different manufacturing companies, which were Pfizer-BioNTech (Cominarty®) (53.6%), Sinovac (CoronaVac®) (27.1%), and Oxford-AstraZeneca (ChAdOx1-S) (19.3%). Since starting the vaccination program, only 77.5% of respondents have received vaccines, mainly in the last two months (58.5%). The experienced side effects were mainly pain/swelling at the injection site, tiredness, muscle pain, and fever (Figure 2). These were similar to those reported by previous studies . The side effects tend to be more pronounced with the second dose, especially those who received the Pfizer-BioNTech (Cominarty®) vaccine. These findings could be further explored in the context of vaccine pre-medications to lessen the severity of side effects. The results showed that males, older individuals (≥60 years), and those receiving the Sinovac (CoronaVac®) vaccine were less likely to experience side effects. Previous research conducted among health care workers in Turkey reported that females and younger individuals were more likely to report vaccine-related side effects . Also, a previous report during the investigation of mRNA vaccines highlighted those older individuals were less likely to experience the vaccine-related systemic side effects .
Interestingly, the number of side effects reported with the Sinovac (CoronaVac®) vaccine was significantly lower than Pfizer-BioNTech and Oxford-AstraZeneca groups. The Sinovac vaccine is an inactivated vaccine, while Pfizer-BioNTech and Oxford-AstraZeneca are nucleic acid and viral vectored vaccines, respectively. Therefore, the differences in the intensity and pattern of side effects could be attributed to the difference in vaccine type as reported previously in comparing potential COVID-19 vaccine candidates . Notably, preliminary reports on the differences between COVID-19 vaccine candidates indicated that Sinovac vaccines might be associated with approximately five times fewer side effects than the other two tested vaccines . Meanwhile, our findings revealed that Sinovac had a 12 times lower correlation with side effects. The side effects after the second dose were more with the Pfizer-BioNTech vaccine, which correlates with the reported data that the systemic side effects of this type of vaccine tend to increase with the second dose . Although several countries have suspended the Oxford-AstraZeneca (ChAdOx1-S) vaccine, especially among younger people, due to reports of vaccine-induced immune thrombocytopenic thrombosis , the public in Malaysia has received this vaccine considering the benefits are outweighed the risks of the disease. The majority of respondents had minor/mild side effects, which were similar to what had been reported by previous studies [32,33], but 10.3% experienced moderately severe to severe side effects, which require further investigation.
In Malaysia, the reported incidence of anaphylaxis following vaccination is quite similar to developed countries. The main allergenic ingredients that have caused anaphylaxis were either polyethylene glycol (PEG) or polysorbate 80. Pfizer-BioNTech and Oxford-AstraZeneca vaccines contained PEG and polysorbate 80, respectively whereas, it is not a case for the Sinovac vaccine. Hence, Sinovac has been used as the alternative vaccine in those who have developed anaphylactic reactions with either Pfizer-BioNTech or Oxford-AstraZeneca vaccines . In addition, the Centers for Disease Control have also reported that severe anaphylaxis after the first dose required immediate treatment and monitoring . Other serious side effects reported in previous studies following the second dose were recurrent Bell’s Palsy from Pfizer-BioNTech  and myocarditis with Moderna .
The study is not without limitations. As a survey-based study, it instinctively exposed to a risk of recall bias, especially among those who received their vaccines significantly earlier than the time of data collection. In addition, the absence of extensive details addressing the management of side effects and their duration for specific types of vaccines. Furthermore, the vaccine hesitancy prevalence should be reported carefully as many study participants have received their vaccination. Finally, it is essential to highlight that the reported severity of side effects was primarily based on individuals’ beliefs, not objective measures.