In the first stage, when the outbreak was only localized in China, on 23 January, the Civil Aviation Authority of Vietnam announced instruction No. 358/CT-CHK regarding a temporary ban of all citizens from Wuhan city, the initial epicenter [7]. The ban was later extended to all flights to and from mainland China [9]. Having a bustling border and a high volume of trade with China, Vietnam was expected to be heavily affected due to the disease’s fast-spreading nature. Recognizing the potential high risks of the disease and limited existing resources, the government focused mainly on preventive measures. Stringent inspections were strictly implemented at airports and land border checkpoints in the form of temperature checks, medical declarations and health checks [20]. All cases with suspicious symptoms were taken in for further diagnosis.

On 12 February, Vietnam and China governments agreed to ease the cross-border restriction to normalize trade in Northern provinces: Quang Ninh, Lai Chau, Lao Cai, Lang Son, and Ha Giang [9]. These trade policy changes had to be carefully considered by the government to strive for the ideal balance between economic and public health security. Trading activities put firm pressure on health workers in the prevention and treatment of COVID-19 in the subsequent disease stages in Vietnam.

As the pandemic widely spread in Deagu, South Korea, the second hotspot after China, the entry ban was further applied to travelers coming from severely affected regions in South Korea, in addition to a mandatory 14-day isolation for all other incoming Korean travelers effective as of 25 February [10]. On 05 March, the Civil Aviation Authority decided to temporarily suspend all flights to South Korea [12]. In this period, a series of emergency and successive restrictions were carried out based on the complex evolution of the disease worldwide, particularly the outbreak in European countries [13]. All international flights were temporarily suspended beginning 19 March and there were considerable reductions in the number of domestic flights [14,43]. Besides, all visa issuance were suspended, except for those on official or diplomatic missions. The border closure timeline in Vietnam was quite aligned with that of other countries in the Southeast Asian region, for example Thailand (22 March), Indonesia (31 March), Singapore (22 March) [3]. It is clear that controlling the epidemic has become the top priority for countries all over the world.

As of February 2, Prime Minister Nguyen Xuan Phuc enacted the Official Dispatch No. 156/CD-TTg enforcing 14-day quarantine for Vietnamese citizens returning from China [16]. On 3 February, the policy was extended to all citizens who entered Vietnam from 31 provinces of China, including foreigners [17]. In the first stage, the policy largely focused on preventing the penetration from the epicenter Wuhan and China in general.

In the second stage being aware of the pandemic danger, the government strictly implemented quarantine measures. On 1 March, citizens who entered the country from epidemic countries (China, Korea, Italy, Iran) have to fill in a health declaration form and follow medical quarantine [20,21]. The newly confirmed cases were mainly foreigners and Vietnamese citizens who returned from European countries or had direct contact with positive patients. Therefore, isolation and quarantine precautions were taken to curb the rise of disease transmission. Several localities at potential high risks of community transmission in Son Loi-Vinh Phuc, Truc Bach-Hanoi and some communities in Hai Phong, Ha Loi-Me Linh were placed in lockdown [25-28]. Bach Mai, a leading hospital at central level with more than 5000 health care workers was locked down in late March after one staff was confirmed positive for COVID-19 [29].

A 15-day nationwide social distancing period began on 1 April led by the principle that “every province and city going into self-isolation” under the Directive No. 16/CT-TTg. Accordingly, everyone – with the exception of essential workers – was required to “shelter in place” and not go out unless for bare necessities such as buying food or drugs [23]. Although there were several considerable inconveniences in implementation of social distancing, most Vietnamese citizens have complied with the government’s regulation. Whereas in the Philippines, the use of weapons had to be deployed to force habitants to follow the government’s measures. On 4 April, an unfortunate incident was recorded in the Philippines as one protester who refused to follow the restriction orders was shot by the police [3]. Back in Vietnam, the number of confirmed cases during this period slightly increased, with over 250 cases in early April [2].

On 16 April, following 15 days of national social distancing, the government divided all localities of the country into ‘high-risk’, ‘at-risk’, and ‘low-risk’ zones to impose precautions accordingly. Hanoi, Ho Chi Minh city – the two biggest metropolitan cities and 10 other provinces had been implementing strict social distancing measures at least until 22. Starting 23 April, most cities and provinces began loosening social distancing requirements to allow more daily routines while still having protective measures in place. Under the guideline, Hanoi and Ho Chi Minh city were expected to intermittently operate daily services [30]. Meanwhile in Thailand, the Prime Minister announced plans to gradually relax restrictions by the end of April owing to the reduction of new confirmed cases. However, in other countries such as Singapore, Philippines and Indonesia, the strict measures continued to be applied until there were clear signs of case decline [3]. The 15-day period had been considered a significant milestone in the prevention of disease transmission in Vietnam. Although there might have been some undiagnosed cases, it cannot be denied that Vietnam’s approach has been well-organized and effectively reduced the speed of transmission.

In the first stage of the pandemic on 2 February, the Ministry of Education and Training announced the closure of all public and private educational institutions across the country [35]. During this period, even though the outbreak was mainly confined to China, the prompt decision of school closing and banning public crowds had shown the advantages of limiting community transmission, which is in line with many other countries’ outcomes [94]. However, the unexpected break has caused students and teachers difficulties in the learning and teaching process. In the meantime, the Ministry of Education and Training was quick to launch innovative distant-learning programs on national television to support students in preparing for their entrance exams [95,96].

During the second stage, restriction measures regarding public gathering were tightened. A series of government documents issued in mid-March had highlighted the importance of social distancing measures and Vietnam’s coping strategies reached a climax of highest stringency levels when the 15-day national social distancing measures took effect on 1 April [23]. The prime objective of the measures was to urgently slow the number of infections or to “flatten the curve” of infection. One of the main priorities was to reduce and cease all non-essential business services, including restaurants, gyms, movie theaters, and religious, sports and cultural gatherings [38]. Many companies and agencies had made the rational decision to allow their employees to work from home, which not only reduced the risk of disease transmission, but also maintained the income for employed individuals. In addition, buses and railroad services were suspended both within a province and between provinces [40].

Upon entering a new phase with fewer new cases as of 23 April, the Ministry of Transport allowed the reoperation of domestic flights as well as reopening of essential transport activities in the whole country [44,97]. In addition, since April 23 most schools were ready to welcome students to return after the long lockdown which had been prolonged since the Lunar New Year [48]. To make schools a safe environment to learn after an extended period of closure required much considerations from localities, which had different operating policies depending on each own economic and social context. At the domestic level, these efforts on limiting exposure dramatically showed positive impacts during a persistent process against the pandemic.

The effective results of the epidemic control to date have been largely contributed by the MOH and their drastic efforts in delivering rapid and decisive responses on all fronts from research, prevention, screening to diagnosis and treatment of COVID-19. In the early days of the outbreak in China, the guideline for diagnosis and treatment of coronavirus infection for Vietnam was already issued by MOH on 16 January and has been continuously updated throughout the epidemic [49-51]. When the COVID-19 outbreak hit Vietnam on 30 Jan, the National Steering Committee and 45 Rapid Response Teams for outbreak prevention and control were established [53,54]. In the wake of the outbreak, MOH’s hotline numbers 19009095 and 19003228 were set up on 1 Feb to address enquiries and concerns, in addition to the local hotlines for counseling provided by each province/city that were launched on 22 March [55,56].

Furthermore, Vietnam has gained substantial achievements in scientific research and development relating to COVID-19. On 7 February, Vietnam became one of the few countries that successfully cultured and isolated the novel coronavirus strain in the laboratory, which would be the premise for further research and development of vaccines, as well as effective prevention interventions against COVID-19 [57]. Moreover, Vietnam officially manufactured the virus detection test kits (RT-PCR and real-time RT-PCR) on 05 March, and was able to manufacture 10 000 test kits per day [60]. To date, the test kit has been approved by WHO and exported to many countries such as: Sweden, Ukraine, Finland, Germany, Italy, Cambodia [98]. The test kit plays a decisive role in the early diagnosis and timely treatment of COVID-19, alongside contact tracing and mass screening in the communities.

Furthermore, a series of guidelines and recommendations on the prevention and control of COVID-19 were released; for example, the guidelines on self-isolation and concentrated quarantine at medical facilities and hotels [65,66,99,100]; guidelines on the prevention and management of COVID-19 for specific vulnerable groups: infants and pregnant women; the elderly and people with chronic diseases [68,69]; recommendations on the prevention of COVID-19 infections in specific places such as apartment buildings, workplaces, public transports, shopping malls, restaurants and others [70-72].

Moreover, the online-based system for medical examination and treatment of COVID-19 infections were launched initially by the Agency of Health Examination and Treatment on 5 February. It was then, officially launched on 18 April by MOH to support hospitals in remote areas regarding medical counselling, consultation, imaging diagnosis, pathology among others [59,64]. The initiative has helped to eliminate geographical and social barriers, and enhanced diagnosis and treatment capacity for COVID-19 in all health facilities.

Furthermore, the government facilitated a robust health care system through issuing a number of Decisions requiring rapid production of medical equipment and suspending exports of anti-COVID-19 drugs to ensure health system capacities during the complicated development of the pandemic [62,63].

Importantly, the government has executed a series of information and communication campaigns to keep the public updated on the most transparent and latest development of the epidemic. On 30 January, communication campaigns via radio, television, newspaper for the prevention and control of the pandemic were launched in all provinces/cities via cooperation between the Department of Health and Department of Information and Communications [73]. On 2 February, the Ministry of Information and Communications issued Directive No. 5/CT-BTTTT strengthening the information campaigns for the prevention and control of the new coronavirus outbreak [74]. Therein, diverse communication channels were set up to reach the entire population. The campaigns consisted of sending text messages to mobile users; producing music videos and short films to widely disseminate anti-COVID information via mass media channels and social networks such as Facebook, Zalo, Youtube, Lotus and trending the hashtag #ICT_anti_nCoV for raising awareness of the epidemic. Through these different streams of media, promotion of awareness and behavioral changes such as wearing masks in public areas and washing hands, was especially timely during the outbreak. Vietnam’s creative communication approach has gone viral and received much attention by viewers, including those from other countries. For example, the parody song 'Ghen Cô Vy', which highlighted the importance of handwashing and personal hygiene to prevent coronavirus infection has gone viral all around the world and was broadcasted on American and French television channels [101].

In line with these activities, websites and applications were sequentially launched such as ‘Vietnam Health’, ‘NCOVI’ ‘Vietnam Health Declaration’, ‘Hanoi Smart City’ and ‘Bluezone’ with the aim of widely disseminating the most updated findings, information, correct misinformation and supporting health care workers to promptly detect suspected cases [64,75-77]. Furthermore, Q&A infographics and leaflets/posters on nCoV infection prevention, which largely targeted drivers and passengers taking public transports, were created and distributed widely [79]. Furthermore, guidance on the correct use of face masks in public was published nationally by MOH on 24 March [78].

In response to the adverse socioeconomic impacts on businesses, society and individuals created by the epidemic, preferential economic policies and relief measures have been implemented [11]. On 7 February, the Ministry of Finance announced a list of medical supplies exempted from tax until the epidemic ended including face masks, hand sanitizers, protective suits [80]. Subsequently, tax payment in some cases had been exempted or deferred and electricity tariffs have been reduced for three months for individuals and enterprises affected by the epidemic [81,83,85].

The COVID-19 pandemic obviously has caused a stir for ASEAN economies [102]. On par with other countries, Vietnam launched several packages of economic stimulus to revive the economy. The Prime Minister issued Directive No. 11/CP on urgent objectives and solutions for assisting businesses facing difficulties and assurance of social welfare amid COVID-19 pandemic on 4 March, in which a credit package of 250 VND billion was debuted [82]. On 10 April, the government announced plans for an economic stimulus package valued 60.9 trillion VND to assist people, numerous enterprises, household businesses and cooperatives facing difficulties due to the pandemic [86], which was officially implemented by the Prime Minister’s Decision on 24 April [87].

Isolated people in health care centers and concentrated quarantine facilities are entitled to around 80 000 VND in allowance per person per day (US $3.4) and all direct medical costs are covered for Vietnamese citizens [88].

Since 24 March, Vietnam has stopped exporting rice to ensure national food security due to the outbreak [89]. Applying the latest digital technology, the Hue Central Hospital created robots that assisted health workers in serving isolated patients in quarantine areas [90]. To reinforce social distancing measures, penalties were imposed for noncompliance of measures including not wearing masks in public places, concealment or dishonesty in self-reporting of health, opening of non-essential businesses, gathering of more than 10 people and spreading ‘fake news’ about the COVID-19 outbreak [91].

Alongside the individual country attempts, ASEAN countries were also united in the fight against the COVID-19 pandemic. Meetings among national senior officers were held in March and April to discuss and share country experiences on COVID-19 prevention, screening and treatment [3,92]. Also, enhancement and strengthening of international cooperation on responses to COVID-19 related health threats is one of the crucial points that were voiced by ASEAN nations [3]. The meetings also convened external experts from the United States, South Korea, Japan and China to share state-of-art technical knowledge and to provide financial support to countries for the current and subsequent waves of the COVID-19 outbreak. [3,92].

Vietnam also made strong efforts to coordinate with international communities in the fight against COVID-19 with the spirit of solidarity – “there is no country alone in the fight against the pandemic”. Since the beginning of April, Vietnam has been transferring medical supply aids to regional neighbors including Cambodia, Indonesia, Laos as well as other developed nations such as the United States, Japan and European countries [93].